1"""gallium
2
3Frontend-tool for Gallium3D architecture.
4
5"""
6
7#
8# Copyright 2008 VMware, Inc.
9# All Rights Reserved.
10#
11# Permission is hereby granted, free of charge, to any person obtaining a
12# copy of this software and associated documentation files (the
13# "Software"), to deal in the Software without restriction, including
14# without limitation the rights to use, copy, modify, merge, publish,
15# distribute, sub license, and/or sell copies of the Software, and to
16# permit persons to whom the Software is furnished to do so, subject to
17# the following conditions:
18#
19# The above copyright notice and this permission notice (including the
20# next paragraph) shall be included in all copies or substantial portions
21# of the Software.
22#
23# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
24# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
26# IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
27# ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
28# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
29# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
30#
31
32
33import distutils.version
34import os
35import os.path
36import re
37import subprocess
38import platform as host_platform
39import sys
40import tempfile
41
42import SCons.Action
43import SCons.Builder
44import SCons.Scanner
45
46
47def symlink(target, source, env):
48    target = str(target[0])
49    source = str(source[0])
50    if os.path.islink(target) or os.path.exists(target):
51        os.remove(target)
52    os.symlink(os.path.basename(source), target)
53
54def install(env, source, subdir):
55    target_dir = os.path.join(env.Dir('#.').srcnode().abspath, env['build_dir'], subdir)
56    return env.Install(target_dir, source)
57
58def install_program(env, source):
59    return install(env, source, 'bin')
60
61def install_shared_library(env, sources, version = ()):
62    targets = []
63    install_dir = os.path.join(env.Dir('#.').srcnode().abspath, env['build_dir'])
64    version = tuple(map(str, version))
65    if env['SHLIBSUFFIX'] == '.dll':
66        dlls = env.FindIxes(sources, 'SHLIBPREFIX', 'SHLIBSUFFIX')
67        targets += install(env, dlls, 'bin')
68        libs = env.FindIxes(sources, 'LIBPREFIX', 'LIBSUFFIX')
69        targets += install(env, libs, 'lib')
70    else:
71        for source in sources:
72            target_dir =  os.path.join(install_dir, 'lib')
73            target_name = '.'.join((str(source),) + version)
74            last = env.InstallAs(os.path.join(target_dir, target_name), source)
75            targets += last
76            while len(version):
77                version = version[:-1]
78                target_name = '.'.join((str(source),) + version)
79                action = SCons.Action.Action(symlink, "  Symlinking $TARGET ...")
80                last = env.Command(os.path.join(target_dir, target_name), last, action)
81                targets += last
82    return targets
83
84
85def msvc2013_compat(env):
86    if env['gcc']:
87        env.Append(CCFLAGS = [
88            '-Werror=vla',
89            '-Werror=pointer-arith',
90        ])
91
92
93def unit_test(env, test_name, program_target, args=None):
94    env.InstallProgram(program_target)
95
96    cmd = [program_target[0].abspath]
97    if args is not None:
98        cmd += args
99    cmd = ' '.join(cmd)
100
101    # http://www.scons.org/wiki/UnitTests
102    action = SCons.Action.Action(cmd, "  Running $SOURCE ...")
103    alias = env.Alias(test_name, program_target, action)
104    env.AlwaysBuild(alias)
105    env.Depends('check', alias)
106
107
108def num_jobs():
109    try:
110        return int(os.environ['NUMBER_OF_PROCESSORS'])
111    except (ValueError, KeyError):
112        pass
113
114    try:
115        return os.sysconf('SC_NPROCESSORS_ONLN')
116    except (ValueError, OSError, AttributeError):
117        pass
118
119    try:
120        return int(os.popen2("sysctl -n hw.ncpu")[1].read())
121    except ValueError:
122        pass
123
124    return 1
125
126
127def check_cc(env, cc, expr, cpp_opt = '-E'):
128    # Invoke C-preprocessor to determine whether the specified expression is
129    # true or not.
130
131    sys.stdout.write('Checking for %s ... ' % cc)
132
133    source = tempfile.NamedTemporaryFile(suffix='.c', delete=False)
134    source.write('#if !(%s)\n#error\n#endif\n' % expr)
135    source.close()
136
137    pipe = SCons.Action._subproc(env, [env['CC'], cpp_opt, source.name],
138                                 stdin = 'devnull',
139                                 stderr = 'devnull',
140                                 stdout = 'devnull')
141    result = pipe.wait() == 0
142
143    os.unlink(source.name)
144
145    sys.stdout.write(' %s\n' % ['no', 'yes'][int(bool(result))])
146    return result
147
148
149def check_prog(env, prog):
150    """Check whether this program exists."""
151
152    sys.stdout.write('Checking for %s ... ' % prog)
153
154    result = env.Detect(prog)
155
156    sys.stdout.write(' %s\n' % ['no', 'yes'][int(bool(result))])
157    return result
158
159
160def generate(env):
161    """Common environment generation code"""
162
163    # Tell tools which machine to compile for
164    env['TARGET_ARCH'] = env['machine']
165    env['MSVS_ARCH'] = env['machine']
166
167    # Toolchain
168    platform = env['platform']
169    env.Tool(env['toolchain'])
170
171    # Allow override compiler and specify additional flags from environment
172    if os.environ.has_key('CC'):
173        env['CC'] = os.environ['CC']
174    if os.environ.has_key('CFLAGS'):
175        env['CCFLAGS'] += SCons.Util.CLVar(os.environ['CFLAGS'])
176    if os.environ.has_key('CXX'):
177        env['CXX'] = os.environ['CXX']
178    if os.environ.has_key('CXXFLAGS'):
179        env['CXXFLAGS'] += SCons.Util.CLVar(os.environ['CXXFLAGS'])
180    if os.environ.has_key('LDFLAGS'):
181        env['LINKFLAGS'] += SCons.Util.CLVar(os.environ['LDFLAGS'])
182
183    # Detect gcc/clang not by executable name, but through pre-defined macros
184    # as autoconf does, to avoid drawing wrong conclusions when using tools
185    # that overrice CC/CXX like scan-build.
186    env['gcc_compat'] = 0
187    env['clang'] = 0
188    env['msvc'] = 0
189    if host_platform.system() == 'Windows':
190        env['msvc'] = check_cc(env, 'MSVC', 'defined(_MSC_VER)', '/E')
191    if not env['msvc']:
192        env['gcc_compat'] = check_cc(env, 'GCC', 'defined(__GNUC__)')
193    env['clang'] = check_cc(env, 'Clang', '__clang__')
194    env['gcc'] = env['gcc_compat'] and not env['clang']
195    env['suncc'] = env['platform'] == 'sunos' and os.path.basename(env['CC']) == 'cc'
196    env['icc'] = 'icc' == os.path.basename(env['CC'])
197
198    if env['msvc'] and env['toolchain'] == 'default' and env['machine'] == 'x86_64':
199        # MSVC x64 support is broken in earlier versions of scons
200        env.EnsurePythonVersion(2, 0)
201
202    # shortcuts
203    machine = env['machine']
204    platform = env['platform']
205    x86 = env['machine'] == 'x86'
206    ppc = env['machine'] == 'ppc'
207    gcc_compat = env['gcc_compat']
208    msvc = env['msvc']
209    suncc = env['suncc']
210    icc = env['icc']
211
212    # Determine whether we are cross compiling; in particular, whether we need
213    # to compile code generators with a different compiler as the target code.
214    hosthost_platform = host_platform.system().lower()
215    if hosthost_platform.startswith('cygwin'):
216        hosthost_platform = 'cygwin'
217    host_machine = os.environ.get('PROCESSOR_ARCHITEW6432', os.environ.get('PROCESSOR_ARCHITECTURE', host_platform.machine()))
218    host_machine = {
219        'x86': 'x86',
220        'i386': 'x86',
221        'i486': 'x86',
222        'i586': 'x86',
223        'i686': 'x86',
224        'ppc' : 'ppc',
225        'AMD64': 'x86_64',
226        'x86_64': 'x86_64',
227    }.get(host_machine, 'generic')
228    env['crosscompile'] = platform != hosthost_platform
229    if machine == 'x86_64' and host_machine != 'x86_64':
230        env['crosscompile'] = True
231    env['hostonly'] = False
232
233    # Backwards compatability with the debug= profile= options
234    if env['build'] == 'debug':
235        if not env['debug']:
236            print 'scons: warning: debug option is deprecated and will be removed eventually; use instead'
237            print
238            print ' scons build=release'
239            print
240            env['build'] = 'release'
241        if env['profile']:
242            print 'scons: warning: profile option is deprecated and will be removed eventually; use instead'
243            print
244            print ' scons build=profile'
245            print
246            env['build'] = 'profile'
247    if False:
248        # Enforce SConscripts to use the new build variable
249        env.popitem('debug')
250        env.popitem('profile')
251    else:
252        # Backwards portability with older sconscripts
253        if env['build'] in ('debug', 'checked'):
254            env['debug'] = True
255            env['profile'] = False
256        if env['build'] == 'profile':
257            env['debug'] = False
258            env['profile'] = True
259        if env['build'] in ('release', 'opt'):
260            env['debug'] = False
261            env['profile'] = False
262
263    # Put build output in a separate dir, which depends on the current
264    # configuration. See also http://www.scons.org/wiki/AdvancedBuildExample
265    build_topdir = 'build'
266    build_subdir = env['platform']
267    if env['embedded']:
268        build_subdir =  'embedded-' + build_subdir
269    if env['machine'] != 'generic':
270        build_subdir += '-' + env['machine']
271    if env['build'] != 'release':
272        build_subdir += '-' +  env['build']
273    build_dir = os.path.join(build_topdir, build_subdir)
274    # Place the .sconsign file in the build dir too, to avoid issues with
275    # different scons versions building the same source file
276    env['build_dir'] = build_dir
277    env.SConsignFile(os.path.join(build_dir, '.sconsign'))
278    if 'SCONS_CACHE_DIR' in os.environ:
279        print 'scons: Using build cache in %s.' % (os.environ['SCONS_CACHE_DIR'],)
280        env.CacheDir(os.environ['SCONS_CACHE_DIR'])
281    env['CONFIGUREDIR'] = os.path.join(build_dir, 'conf')
282    env['CONFIGURELOG'] = os.path.join(os.path.abspath(build_dir), 'config.log')
283
284    # Parallel build
285    if env.GetOption('num_jobs') <= 1:
286        env.SetOption('num_jobs', num_jobs())
287
288    env.Decider('MD5-timestamp')
289    env.SetOption('max_drift', 60)
290
291    # C preprocessor options
292    cppdefines = []
293    cppdefines += [
294        '__STDC_LIMIT_MACROS',
295        '__STDC_CONSTANT_MACROS',
296        'HAVE_NO_AUTOCONF',
297    ]
298    if env['build'] in ('debug', 'checked'):
299        cppdefines += ['DEBUG']
300    else:
301        cppdefines += ['NDEBUG']
302    if env['build'] == 'profile':
303        cppdefines += ['PROFILE']
304    if env['build'] in ('opt', 'profile'):
305        cppdefines += ['VMX86_STATS']
306    if env['platform'] in ('posix', 'linux', 'freebsd', 'darwin'):
307        cppdefines += [
308            '_POSIX_SOURCE',
309            ('_POSIX_C_SOURCE', '199309L'),
310            '_SVID_SOURCE',
311            '_BSD_SOURCE',
312            '_GNU_SOURCE',
313            '_DEFAULT_SOURCE',
314        ]
315        if env['platform'] == 'darwin':
316            cppdefines += [
317                '_DARWIN_C_SOURCE',
318                'GLX_USE_APPLEGL',
319                'GLX_DIRECT_RENDERING',
320            ]
321        else:
322            cppdefines += [
323                'GLX_DIRECT_RENDERING',
324                'GLX_INDIRECT_RENDERING',
325            ]
326
327        if env['platform'] in ('linux', 'darwin'):
328            cppdefines += ['HAVE_XLOCALE_H']
329
330    if platform == 'windows':
331        cppdefines += [
332            'WIN32',
333            '_WINDOWS',
334            #'_UNICODE',
335            #'UNICODE',
336            # http://msdn.microsoft.com/en-us/library/aa383745.aspx
337            ('_WIN32_WINNT', '0x0601'),
338            ('WINVER', '0x0601'),
339        ]
340        if gcc_compat:
341            cppdefines += [('__MSVCRT_VERSION__', '0x0700')]
342        if msvc:
343            cppdefines += [
344                'VC_EXTRALEAN',
345                '_USE_MATH_DEFINES',
346                '_CRT_SECURE_NO_WARNINGS',
347                '_CRT_SECURE_NO_DEPRECATE',
348                '_SCL_SECURE_NO_WARNINGS',
349                '_SCL_SECURE_NO_DEPRECATE',
350                '_ALLOW_KEYWORD_MACROS',
351                '_HAS_EXCEPTIONS=0', # Tell C++ STL to not use exceptions
352            ]
353        if env['build'] in ('debug', 'checked'):
354            cppdefines += ['_DEBUG']
355    if platform == 'windows':
356        cppdefines += ['PIPE_SUBSYSTEM_WINDOWS_USER']
357    if env['embedded']:
358        cppdefines += ['PIPE_SUBSYSTEM_EMBEDDED']
359    if env['texture_float']:
360        print 'warning: Floating-point textures enabled.'
361        print 'warning: Please consult docs/patents.txt with your lawyer before building Mesa.'
362        cppdefines += ['TEXTURE_FLOAT_ENABLED']
363    env.Append(CPPDEFINES = cppdefines)
364
365    # C compiler options
366    cflags = [] # C
367    cxxflags = [] # C++
368    ccflags = [] # C & C++
369    if gcc_compat:
370        if env['build'] == 'debug':
371            ccflags += ['-O0']
372        else:
373            ccflags += ['-O3']
374        if env['gcc']:
375            # gcc's builtin memcmp is slower than glibc's
376            # http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43052
377            ccflags += ['-fno-builtin-memcmp']
378        # Work around aliasing bugs - developers should comment this out
379        ccflags += ['-fno-strict-aliasing']
380        ccflags += ['-g']
381        if env['build'] in ('checked', 'profile') or env['asan']:
382            # See http://code.google.com/p/jrfonseca/wiki/Gprof2Dot#Which_options_should_I_pass_to_gcc_when_compiling_for_profiling?
383            ccflags += [
384                '-fno-omit-frame-pointer',
385            ]
386            if env['gcc']:
387                ccflags += ['-fno-optimize-sibling-calls']
388        if env['machine'] == 'x86':
389            ccflags += [
390                '-m32',
391                #'-march=pentium4',
392            ]
393            if platform != 'haiku':
394                # NOTE: We need to ensure stack is realigned given that we
395                # produce shared objects, and have no control over the stack
396                # alignment policy of the application. Therefore we need
397                # -mstackrealign ore -mincoming-stack-boundary=2.
398                #
399                # XXX: We could have SSE without -mstackrealign if we always used
400                # __attribute__((force_align_arg_pointer)), but that's not
401                # always the case.
402                ccflags += [
403                    '-mstackrealign', # ensure stack is aligned
404                    '-msse', '-msse2', # enable SIMD intrinsics
405                    '-mfpmath=sse', # generate SSE floating-point arithmetic
406                ]
407            if platform in ['windows', 'darwin']:
408                # Workaround http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216
409                ccflags += ['-fno-common']
410            if platform in ['haiku']:
411                # Make optimizations compatible with Pentium or higher on Haiku
412                ccflags += [
413                    '-mstackrealign', # ensure stack is aligned
414                    '-march=i586', # Haiku target is Pentium
415                    '-mtune=i686' # use i686 where we can
416                ]
417        if env['machine'] == 'x86_64':
418            ccflags += ['-m64']
419            if platform == 'darwin':
420                ccflags += ['-fno-common']
421        if env['platform'] not in ('cygwin', 'haiku', 'windows'):
422            ccflags += ['-fvisibility=hidden']
423        # See also:
424        # - http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
425        ccflags += [
426            '-Wall',
427            '-Wno-long-long',
428            '-fmessage-length=0', # be nice to Eclipse
429        ]
430        cflags += [
431            '-Wmissing-prototypes',
432            '-std=gnu99',
433        ]
434    if icc:
435        cflags += [
436            '-std=gnu99',
437        ]
438    if msvc:
439        # See also:
440        # - http://msdn.microsoft.com/en-us/library/19z1t1wy.aspx
441        # - cl /?
442        if env['build'] == 'debug':
443            ccflags += [
444              '/Od', # disable optimizations
445              '/Oi', # enable intrinsic functions
446            ]
447        else:
448            ccflags += [
449                '/O2', # optimize for speed
450            ]
451        if env['build'] in ('release', 'opt'):
452            if not env['clang']:
453                ccflags += [
454                    '/GL', # enable whole program optimization
455                ]
456        else:
457            ccflags += [
458                '/Oy-', # disable frame pointer omission
459            ]
460        ccflags += [
461            '/W3', # warning level
462            '/wd4018', # signed/unsigned mismatch
463            '/wd4056', # overflow in floating-point constant arithmetic
464            '/wd4244', # conversion from 'type1' to 'type2', possible loss of data
465            '/wd4267', # 'var' : conversion from 'size_t' to 'type', possible loss of data
466            '/wd4305', # truncation from 'type1' to 'type2'
467            '/wd4351', # new behavior: elements of array 'array' will be default initialized
468            '/wd4756', # overflow in constant arithmetic
469            '/wd4800', # forcing value to bool 'true' or 'false' (performance warning)
470            '/wd4996', # disable deprecated POSIX name warnings
471        ]
472        if env['clang']:
473            ccflags += [
474                '-Wno-microsoft-enum-value', # enumerator value is not representable in underlying type 'int'
475            ]
476        if env['machine'] == 'x86':
477            ccflags += [
478                '/arch:SSE2', # use the SSE2 instructions (default since MSVC 2012)
479            ]
480        if platform == 'windows':
481            ccflags += [
482                # TODO
483            ]
484        # Automatic pdb generation
485        # See http://scons.tigris.org/issues/show_bug.cgi?id=1656
486        env.EnsureSConsVersion(0, 98, 0)
487        env['PDB'] = '${TARGET.base}.pdb'
488    env.Append(CCFLAGS = ccflags)
489    env.Append(CFLAGS = cflags)
490    env.Append(CXXFLAGS = cxxflags)
491
492    if env['platform'] == 'windows' and msvc:
493        # Choose the appropriate MSVC CRT
494        # http://msdn.microsoft.com/en-us/library/2kzt1wy3.aspx
495        if env['build'] in ('debug', 'checked'):
496            env.Append(CCFLAGS = ['/MTd'])
497            env.Append(SHCCFLAGS = ['/LDd'])
498        else:
499            env.Append(CCFLAGS = ['/MT'])
500            env.Append(SHCCFLAGS = ['/LD'])
501
502    # Static code analysis
503    if env['analyze']:
504        if env['msvc']:
505            # http://msdn.microsoft.com/en-us/library/ms173498.aspx
506            env.Append(CCFLAGS = [
507                '/analyze',
508                #'/analyze:log', '${TARGET.base}.xml',
509                '/wd28251', # Inconsistent annotation for function
510            ])
511        if env['clang']:
512            # scan-build will produce more comprehensive output
513            env.Append(CCFLAGS = ['--analyze'])
514
515    # https://github.com/google/sanitizers/wiki/AddressSanitizer
516    if env['asan']:
517        if gcc_compat:
518            env.Append(CCFLAGS = [
519                '-fsanitize=address',
520            ])
521            env.Append(LINKFLAGS = [
522                '-fsanitize=address',
523            ])
524
525    # Assembler options
526    if gcc_compat:
527        if env['machine'] == 'x86':
528            env.Append(ASFLAGS = ['-m32'])
529        if env['machine'] == 'x86_64':
530            env.Append(ASFLAGS = ['-m64'])
531
532    # Linker options
533    linkflags = []
534    shlinkflags = []
535    if gcc_compat:
536        if env['machine'] == 'x86':
537            linkflags += ['-m32']
538        if env['machine'] == 'x86_64':
539            linkflags += ['-m64']
540        if env['platform'] not in ('darwin'):
541            shlinkflags += [
542                '-Wl,-Bsymbolic',
543            ]
544        # Handle circular dependencies in the libraries
545        if env['platform'] in ('darwin'):
546            pass
547        else:
548            env['_LIBFLAGS'] = '-Wl,--start-group ' + env['_LIBFLAGS'] + ' -Wl,--end-group'
549        if env['platform'] == 'windows':
550            linkflags += [
551                '-Wl,--nxcompat', # DEP
552                '-Wl,--dynamicbase', # ASLR
553            ]
554            # Avoid depending on gcc runtime DLLs
555            linkflags += ['-static-libgcc']
556            if 'w64' in env['CC'].split('-'):
557                linkflags += ['-static-libstdc++']
558            # Handle the @xx symbol munging of DLL exports
559            shlinkflags += ['-Wl,--enable-stdcall-fixup']
560            #shlinkflags += ['-Wl,--kill-at']
561    if msvc:
562        if env['build'] in ('release', 'opt') and not env['clang']:
563            # enable Link-time Code Generation
564            linkflags += ['/LTCG']
565            env.Append(ARFLAGS = ['/LTCG'])
566    if platform == 'windows' and msvc:
567        # See also:
568        # - http://msdn2.microsoft.com/en-us/library/y0zzbyt4.aspx
569        linkflags += [
570            '/fixed:no',
571            '/incremental:no',
572            '/dynamicbase', # ASLR
573            '/nxcompat', # DEP
574        ]
575    env.Append(LINKFLAGS = linkflags)
576    env.Append(SHLINKFLAGS = shlinkflags)
577
578    # We have C++ in several libraries, so always link with the C++ compiler
579    if gcc_compat:
580        env['LINK'] = env['CXX']
581
582    # Default libs
583    libs = []
584    if env['platform'] in ('darwin', 'freebsd', 'linux', 'posix', 'sunos'):
585        libs += ['m', 'pthread', 'dl']
586    if env['platform'] in ('linux',):
587        libs += ['rt']
588    if env['platform'] in ('haiku'):
589        libs += ['root', 'be', 'network', 'translation']
590    env.Append(LIBS = libs)
591
592    # OpenMP
593    if env['openmp']:
594        if env['msvc']:
595            env.Append(CCFLAGS = ['/openmp'])
596            # When building openmp release VS2008 link.exe crashes with LNK1103 error.
597            # Workaround: overwrite PDB flags with empty value as it isn't required anyways
598            if env['build'] == 'release':
599                env['PDB'] = ''
600        if env['gcc']:
601            env.Append(CCFLAGS = ['-fopenmp'])
602            env.Append(LIBS = ['gomp'])
603
604    # Load tools
605    env.Tool('lex')
606    if env['msvc']:
607        env.Append(LEXFLAGS = [
608            # Force flex to use const keyword in prototypes, as relies on
609            # __cplusplus or __STDC__ macro to determine whether it's safe to
610            # use const keyword, but MSVC never defines __STDC__ unless we
611            # disable all MSVC extensions.
612            '-DYY_USE_CONST=',
613        ])
614        # Flex relies on __STDC_VERSION__>=199901L to decide when to include
615        # C99 inttypes.h.  We always have inttypes.h available with MSVC
616        # (either the one bundled with MSVC 2013, or the one we bundle
617        # ourselves), but we can't just define __STDC_VERSION__ without
618        # breaking stuff, as MSVC doesn't fully support C99.  There's also no
619        # way to premptively include stdint.
620        env.Append(CCFLAGS = ['-FIinttypes.h'])
621    if host_platform.system() == 'Windows':
622        # Prefer winflexbison binaries, as not only they are easier to install
623        # (no additional dependencies), but also better Windows support.
624        if check_prog(env, 'win_flex'):
625            env["LEX"] = 'win_flex'
626            env.Append(LEXFLAGS = [
627                # windows compatibility (uses <io.h> instead of <unistd.h> and
628                # _isatty, _fileno functions)
629                '--wincompat'
630            ])
631
632    env.Tool('yacc')
633    if host_platform.system() == 'Windows':
634        if check_prog(env, 'win_bison'):
635            env["YACC"] = 'win_bison'
636
637    if env['llvm']:
638        env.Tool('llvm')
639
640    # Custom builders and methods
641    env.Tool('custom')
642    env.AddMethod(install_program, 'InstallProgram')
643    env.AddMethod(install_shared_library, 'InstallSharedLibrary')
644    env.AddMethod(msvc2013_compat, 'MSVC2013Compat')
645    env.AddMethod(unit_test, 'UnitTest')
646
647    env.PkgCheckModules('X11', ['x11', 'xext', 'xdamage', 'xfixes', 'glproto >= 1.4.13'])
648    env.PkgCheckModules('XCB', ['x11-xcb', 'xcb-glx >= 1.8.1', 'xcb-dri2 >= 1.8'])
649    env.PkgCheckModules('XF86VIDMODE', ['xxf86vm'])
650    env.PkgCheckModules('DRM', ['libdrm >= 2.4.66'])
651
652    if env['x11']:
653        env.Append(CPPPATH = env['X11_CPPPATH'])
654
655    env['dri'] = env['x11'] and env['drm']
656
657    # for debugging
658    #print env.Dump()
659
660
661def exists(env):
662    return 1
663