1 # a waf tool to add autoconf-like macros to the configure section
4 from waflib import Build, Options, Logs, Context
5 from waflib.Configure import conf
6 from waflib.TaskGen import feature
7 from waflib.Tools import c_preproc as preproc
8 from samba_utils import TO_LIST, GET_TARGET_TYPE, SET_TARGET_TYPE, unique_list, mkdir_p
10 missing_headers = set()
12 ####################################################
13 # some autoconf like helpers, to make the transition
14 # to waf a bit easier for those used to autoconf
18 def DEFINE(conf, d, v, add_to_cflags=False, quote=False):
19 '''define a config option'''
20 conf.define(d, v, quote=quote)
22 conf.env.append_value('CFLAGS', '-D%s=%s' % (d, str(v)))
24 def hlist_to_string(conf, headers=None):
25 '''convert a headers list to a set of #include lines'''
27 hlist = conf.env.hlist
30 hlist.extend(TO_LIST(headers))
32 hdrs += '#include <%s>\n' % h
37 def COMPOUND_START(conf, msg):
38 '''start a compound test'''
39 def null_check_message_1(self,*k,**kw):
41 def null_check_message_2(self,*k,**kw):
44 v = getattr(conf.env, 'in_compound', [])
45 if v != [] and v != 0:
46 conf.env.in_compound = v + 1
49 conf.saved_check_message_1 = conf.start_msg
50 conf.start_msg = null_check_message_1
51 conf.saved_check_message_2 = conf.end_msg
52 conf.end_msg = null_check_message_2
53 conf.env.in_compound = 1
57 def COMPOUND_END(conf, result):
58 '''start a compound test'''
59 conf.env.in_compound -= 1
60 if conf.env.in_compound != 0:
62 conf.start_msg = conf.saved_check_message_1
63 conf.end_msg = conf.saved_check_message_2
68 p('not found', 'YELLOW')
75 '''using the nolink type in conf.check() allows us to avoid
76 the link stage of a test, thus speeding it up for tests
77 that where linking is not needed'''
81 def CHECK_HEADER(conf, h, add_headers=False, lib=None):
82 '''check for a header'''
83 if h in missing_headers and lib is None:
85 d = h.upper().replace('/', '_')
86 d = d.replace('.', '_')
87 d = d.replace('-', '_')
89 if CONFIG_SET(conf, d):
91 if not h in conf.env.hlist:
92 conf.env.hlist.append(h)
95 (ccflags, ldflags, cpppath) = library_flags(conf, lib)
97 hdrs = hlist_to_string(conf, headers=h)
100 ret = conf.check(fragment='%s\nint main(void) { return 0; }' % hdrs,
107 msg="Checking for header %s" % h)
109 missing_headers.add(h)
113 if add_headers and not h in conf.env.hlist:
114 conf.env.hlist.append(h)
119 def CHECK_HEADERS(conf, headers, add_headers=False, together=False, lib=None):
120 '''check for a list of headers
122 when together==True, then the headers accumulate within this test.
123 This is useful for interdependent headers
126 if not add_headers and together:
127 saved_hlist = conf.env.hlist[:]
128 set_add_headers = True
130 set_add_headers = add_headers
131 for hdr in TO_LIST(headers):
132 if not CHECK_HEADER(conf, hdr, set_add_headers, lib=lib):
134 if not add_headers and together:
135 conf.env.hlist = saved_hlist
139 def header_list(conf, headers=None, lib=None):
140 '''form a list of headers which exist, as a string'''
142 if headers is not None:
143 for h in TO_LIST(headers):
144 if CHECK_HEADER(conf, h, add_headers=False, lib=lib):
146 return hlist_to_string(conf, headers=hlist)
150 def CHECK_TYPE(conf, t, alternate=None, headers=None, define=None, lib=None, msg=None):
151 '''check for a single type'''
153 define = 'HAVE_' + t.upper().replace(' ', '_')
155 msg='Checking for %s' % t
156 ret = CHECK_CODE(conf, '%s _x' % t,
164 if not ret and alternate:
165 conf.DEFINE(t, alternate)
170 def CHECK_TYPES(conf, list, headers=None, define=None, alternate=None, lib=None):
171 '''check for a list of types'''
173 for t in TO_LIST(list):
174 if not CHECK_TYPE(conf, t, headers=headers,
175 define=define, alternate=alternate, lib=lib):
181 def CHECK_TYPE_IN(conf, t, headers=None, alternate=None, define=None):
182 '''check for a single type with a header'''
183 return CHECK_TYPE(conf, t, headers=headers, alternate=alternate, define=define)
187 def CHECK_VARIABLE(conf, v, define=None, always=False,
188 headers=None, msg=None, lib=None):
189 '''check for a variable declaration (or define)'''
191 define = 'HAVE_%s' % v.upper()
194 msg="Checking for variable %s" % v
196 return CHECK_CODE(conf,
197 # we need to make sure the compiler doesn't
201 void *_x; _x=(void *)&%s; return (int)_x;
216 def CHECK_DECLS(conf, vars, reverse=False, headers=None, always=False):
217 '''check a list of variable declarations, using the HAVE_DECL_xxx form
220 When reverse==True then use HAVE_xxx_DECL instead of HAVE_DECL_xxx
223 for v in TO_LIST(vars):
225 define='HAVE_DECL_%s' % v.upper()
227 define='HAVE_%s_DECL' % v.upper()
228 if not CHECK_VARIABLE(conf, v,
231 msg='Checking for declaration of %s' % v,
233 if not CHECK_CODE(conf,
239 msg='Checking for declaration of %s (as enum)' % v,
248 def CHECK_FUNC(conf, f, link=True, lib=None, headers=None):
249 '''check for a function'''
250 define='HAVE_%s' % f.upper()
254 conf.COMPOUND_START('Checking for %s' % f)
256 if link is None or link:
257 ret = CHECK_CODE(conf,
258 # this is based on the autoconf strategy
260 #define %s __fake__%s
267 #if defined __stub_%s || defined __stub___%s
268 #error "bad glibc stub"
271 int main() { return %s(); }
272 ''' % (f, f, f, f, f, f, f),
281 msg='Checking for %s' % f)
284 ret = CHECK_CODE(conf,
285 # it might be a macro
286 # we need to make sure the compiler doesn't
288 'void *__x = (void *)%s; return (int)__x' % f,
297 msg='Checking for macro %s' % f)
299 if not ret and (link is None or not link):
300 ret = CHECK_VARIABLE(conf, f,
303 msg='Checking for declaration of %s' % f)
304 conf.COMPOUND_END(ret)
309 def CHECK_FUNCS(conf, list, link=True, lib=None, headers=None):
310 '''check for a list of functions'''
312 for f in TO_LIST(list):
313 if not CHECK_FUNC(conf, f, link=link, lib=lib, headers=headers):
319 def CHECK_SIZEOF(conf, vars, headers=None, define=None, critical=True):
320 '''check the size of a type'''
321 for v in TO_LIST(vars):
325 v_define = 'SIZEOF_%s' % v.upper().replace(' ', '_')
326 for size in list((1, 2, 4, 8, 16, 32)):
328 'static int test_array[1 - 2 * !(((long int)(sizeof(%s))) <= %d)];' % (v, size),
333 msg="Checking if size of %s == %d" % (v, size)):
334 conf.DEFINE(v_define, size)
337 if not ret and critical:
338 Logs.error("Couldn't determine size of '%s'" % v)
343 def CHECK_VALUEOF(conf, v, headers=None, define=None):
344 '''check the value of a variable/define'''
348 v_define = 'VALUEOF_%s' % v.upper().replace(' ', '_')
350 'printf("%%u", (unsigned)(%s))' % v,
357 msg="Checking value of %s" % v):
358 return int(conf.env[v_define])
363 def CHECK_CODE(conf, code, define,
364 always=False, execute=False, addmain=True,
365 add_headers=True, mandatory=False,
366 headers=None, msg=None, cflags='', includes='# .',
367 local_include=True, lib=None, link=True,
368 define_ret=False, quote=False,
369 on_target=True, strict=False):
370 '''check if some code compiles and/or runs'''
372 if CONFIG_SET(conf, define):
375 if headers is not None:
376 CHECK_HEADERS(conf, headers=headers, lib=lib)
379 hdrs = header_list(conf, headers=headers, lib=lib)
388 fragment='%s\n int main(void) { %s; return 0; }\n' % (hdrs, code)
390 fragment='%s\n%s\n' % (hdrs, code)
393 msg="Checking for %s" % define
395 cflags = TO_LIST(cflags)
397 # Be strict when relying on a compiler check
398 # Some compilers (e.g. xlc) ignore non-supported features as warnings
401 if conf.env["CC_NAME"] == "gcc":
402 extra_cflags = "-Werror"
403 elif conf.env["CC_NAME"] == "xlc":
404 extra_cflags = "-qhalt=w"
406 cflags.append(extra_cflags)
409 cflags.append('-I%s' % conf.path.abspath())
416 uselib = TO_LIST(lib)
418 (ccflags, ldflags, cpppath) = library_flags(conf, uselib)
420 includes = TO_LIST(includes)
421 includes.extend(cpppath)
423 uselib = [l.upper() for l in uselib]
425 cflags.extend(ccflags)
428 exec_args = conf.SAMBA_CROSS_ARGS(msg=msg)
432 conf.COMPOUND_START(msg)
435 ret = conf.check(fragment=fragment,
437 define_name = define,
446 define_ret=define_ret)
449 conf.DEFINE(define, 0)
451 conf.undefine(define)
452 conf.COMPOUND_END(False)
457 # Success is indicated by ret but we should unset
458 # defines set by WAF's c_config.check() because it
459 # defines it to int(ret) and we want to undefine it
461 conf.undefine(define)
462 conf.COMPOUND_END(False)
465 conf.DEFINE(define, 1)
466 conf.COMPOUND_END(True)
468 conf.DEFINE(define, ret, quote=quote)
469 conf.COMPOUND_END(ret)
474 def CHECK_STRUCTURE_MEMBER(conf, structname, member,
475 always=False, define=None, headers=None,
477 '''check for a structure member'''
479 define = 'HAVE_%s' % member.upper()
480 return CHECK_CODE(conf,
481 '%s s; void *_x; _x=(void *)&s.%s' % (structname, member),
489 msg="Checking for member %s in %s" % (member, structname))
493 def CHECK_CFLAGS(conf, cflags, fragment='int main(void) { return 0; }\n'):
494 '''check if the given cflags are accepted by the compiler
496 check_cflags = TO_LIST(cflags)
497 if 'WERROR_CFLAGS' in conf.env:
498 check_cflags.extend(conf.env['WERROR_CFLAGS'])
499 return conf.check(fragment=fragment,
504 msg="Checking compiler accepts %s" % cflags)
507 def CHECK_LDFLAGS(conf, ldflags):
508 '''check if the given ldflags are accepted by the linker
510 return conf.check(fragment='int main(void) { return 0; }\n',
514 msg="Checking linker accepts %s" % ldflags)
518 def CONFIG_GET(conf, option):
519 '''return True if a configuration option was found'''
520 if (option in conf.env):
521 return conf.env[option]
526 def CONFIG_SET(conf, option):
527 '''return True if a configuration option was found'''
528 if option not in conf.env:
540 def CONFIG_RESET(conf, option):
541 if option not in conf.env:
545 Build.BuildContext.CONFIG_RESET = CONFIG_RESET
546 Build.BuildContext.CONFIG_SET = CONFIG_SET
547 Build.BuildContext.CONFIG_GET = CONFIG_GET
550 def library_flags(self, libs):
551 '''work out flags from pkg_config'''
555 for lib in TO_LIST(libs):
556 # note that we do not add the -I and -L in here, as that is added by the waf
557 # core. Adding it here would just change the order that it is put on the link line
558 # which can cause system paths to be added before internal libraries
559 extra_ccflags = TO_LIST(getattr(self.env, 'CFLAGS_%s' % lib.upper(), []))
560 extra_ldflags = TO_LIST(getattr(self.env, 'LDFLAGS_%s' % lib.upper(), []))
561 extra_cpppath = TO_LIST(getattr(self.env, 'CPPPATH_%s' % lib.upper(), []))
562 ccflags.extend(extra_ccflags)
563 ldflags.extend(extra_ldflags)
564 cpppath.extend(extra_cpppath)
566 extra_cpppath = TO_LIST(getattr(self.env, 'INCLUDES_%s' % lib.upper(), []))
567 cpppath.extend(extra_cpppath)
568 if 'EXTRA_LDFLAGS' in self.env:
569 ldflags.extend(self.env['EXTRA_LDFLAGS'])
571 ccflags = unique_list(ccflags)
572 ldflags = unique_list(ldflags)
573 cpppath = unique_list(cpppath)
574 return (ccflags, ldflags, cpppath)
578 def CHECK_LIB(conf, libs, mandatory=False, empty_decl=True, set_target=True, shlib=False):
579 '''check if a set of libraries exist as system libraries
581 returns the sublist of libs that do exist as a syslib or []
592 liblist = TO_LIST(libs)
593 for lib in liblist[:]:
594 if GET_TARGET_TYPE(conf, lib) == 'SYSLIB':
598 (ccflags, ldflags, cpppath) = library_flags(conf, lib)
600 res = conf.check(features='c cshlib', fragment=fragment, lib=lib, uselib_store=lib, cflags=ccflags, ldflags=ldflags, uselib=lib.upper(), mandatory=False)
602 res = conf.check(lib=lib, uselib_store=lib, cflags=ccflags, ldflags=ldflags, uselib=lib.upper(), mandatory=False)
606 Logs.error("Mandatory library '%s' not found for functions '%s'" % (lib, list))
609 # if it isn't a mandatory library, then remove it from dependency lists
611 SET_TARGET_TYPE(conf, lib, 'EMPTY')
613 conf.define('HAVE_LIB%s' % lib.upper().replace('-','_').replace('.','_'), 1)
614 conf.env['LIB_' + lib.upper()] = lib
616 conf.SET_TARGET_TYPE(lib, 'SYSLIB')
624 def CHECK_FUNCS_IN(conf, list, library, mandatory=False, checklibc=False,
625 headers=None, link=True, empty_decl=True, set_target=True):
627 check that the functions in 'list' are available in 'library'
628 if they are, then make that library available as a dependency
630 if the library is not available and mandatory==True, then
633 If the library is not available and mandatory==False, then
634 add the library to the list of dependencies to remove from
637 optionally check for the functions first in libc
639 remaining = TO_LIST(list)
640 liblist = TO_LIST(library)
642 # check if some already found
643 for f in remaining[:]:
644 if CONFIG_SET(conf, 'HAVE_%s' % f.upper()):
647 # see if the functions are in libc
649 for f in remaining[:]:
650 if CHECK_FUNC(conf, f, link=True, headers=headers):
655 if GET_TARGET_TYPE(conf, lib) != 'SYSLIB' and empty_decl:
656 SET_TARGET_TYPE(conf, lib, 'EMPTY')
659 checklist = conf.CHECK_LIB(liblist, empty_decl=empty_decl, set_target=set_target)
660 for lib in liblist[:]:
661 if not lib in checklist and mandatory:
662 Logs.error("Mandatory library '%s' not found for functions '%s'" % (lib, list))
667 if not CHECK_FUNC(conf, f, lib=' '.join(checklist), headers=headers, link=link):
674 def IN_LAUNCH_DIR(conf):
675 '''return True if this rule is being run from the launch directory'''
676 return os.path.realpath(conf.path.abspath()) == os.path.realpath(Context.launch_dir)
677 Options.OptionsContext.IN_LAUNCH_DIR = IN_LAUNCH_DIR
681 def SAMBA_CONFIG_H(conf, path=None):
682 '''write out config.h in the right directory'''
683 # we don't want to produce a config.h in places like lib/replace
684 # when we are building projects that depend on lib/replace
685 if not IN_LAUNCH_DIR(conf):
688 # we need to build real code that can't be optimized away to test
689 stack_protect_list = ['-fstack-protector-strong', '-fstack-protector']
690 for stack_protect_flag in stack_protect_list:
691 flag_supported = conf.check(fragment='''
697 while (fgets(t, sizeof(t), stdin));
702 cflags=[ '-Werror', '-Wp,-D_FORTIFY_SOURCE=2', stack_protect_flag],
704 msg='Checking if compiler accepts %s' % (stack_protect_flag))
706 conf.ADD_CFLAGS('-Wp,-D_FORTIFY_SOURCE=2 %s' % (stack_protect_flag))
709 flag_supported = conf.check(fragment='''
715 while (fgets(t, sizeof(t), stdin));
720 cflags=[ '-Werror', '-fstack-clash-protection'],
722 msg='Checking if compiler accepts -fstack-clash-protection')
724 conf.ADD_CFLAGS('-fstack-clash-protection')
726 if Options.options.debug:
727 conf.ADD_CFLAGS('-g', testflags=True)
729 if Options.options.developer:
730 conf.env.DEVELOPER_MODE = True
732 conf.ADD_CFLAGS('-g', testflags=True)
733 conf.ADD_CFLAGS('-Wall', testflags=True)
734 conf.ADD_CFLAGS('-Wshadow', testflags=True)
735 conf.ADD_CFLAGS('-Wmissing-prototypes', testflags=True)
736 conf.ADD_CFLAGS('-Wcast-align -Wcast-qual', testflags=True)
737 conf.ADD_CFLAGS('-fno-common', testflags=True)
739 conf.ADD_CFLAGS('-Werror=address', testflags=True)
740 # we add these here to ensure that -Wstrict-prototypes is not set during configure
741 conf.ADD_CFLAGS('-Werror=strict-prototypes -Wstrict-prototypes',
743 conf.ADD_CFLAGS('-Werror=write-strings -Wwrite-strings',
745 conf.ADD_CFLAGS('-Werror-implicit-function-declaration',
747 conf.ADD_CFLAGS('-Werror=pointer-arith -Wpointer-arith',
749 conf.ADD_CFLAGS('-Werror=declaration-after-statement -Wdeclaration-after-statement',
751 conf.ADD_CFLAGS('-Werror=return-type -Wreturn-type',
753 conf.ADD_CFLAGS('-Werror=uninitialized -Wuninitialized',
755 conf.ADD_CFLAGS('-Wimplicit-fallthrough',
757 conf.ADD_CFLAGS('-Werror=strict-overflow -Wstrict-overflow=2',
760 conf.ADD_CFLAGS('-Wformat=2 -Wno-format-y2k', testflags=True)
761 conf.ADD_CFLAGS('-Wno-format-zero-length', testflags=True)
762 conf.ADD_CFLAGS('-Werror=format-security -Wformat-security',
763 testflags=True, prereq_flags='-Wformat')
764 # This check is because for ldb_search(), a NULL format string
765 # is not an error, but some compilers complain about that.
766 if CHECK_CFLAGS(conf, ["-Werror=format", "-Wformat=2"], '''
767 int testformat(char *format, ...) __attribute__ ((format (__printf__, 1, 2)));
775 if not 'EXTRA_CFLAGS' in conf.env:
776 conf.env['EXTRA_CFLAGS'] = []
777 conf.env['EXTRA_CFLAGS'].extend(TO_LIST("-Werror=format"))
779 if Options.options.picky_developer:
780 conf.ADD_NAMED_CFLAGS('PICKY_CFLAGS', '-Werror -Wno-error=deprecated-declarations', testflags=True)
781 conf.ADD_NAMED_CFLAGS('PICKY_CFLAGS', '-Wno-error=tautological-compare', testflags=True)
783 if Options.options.fatal_errors:
784 conf.ADD_CFLAGS('-Wfatal-errors', testflags=True)
786 if Options.options.pedantic:
787 conf.ADD_CFLAGS('-W', testflags=True)
789 if Options.options.address_sanitizer:
790 conf.ADD_CFLAGS('-fno-omit-frame-pointer -O1 -fsanitize=address', testflags=True)
791 conf.ADD_LDFLAGS('-fsanitize=address', testflags=True)
792 conf.env['ADDRESS_SANITIZER'] = True
795 # Let people pass an additional ADDITIONAL_{CFLAGS,LDFLAGS}
796 # environment variables which are only used the for final build.
798 # The CFLAGS and LDFLAGS environment variables are also
799 # used for the configure checks which might impact their results.
800 conf.add_os_flags('ADDITIONAL_CFLAGS')
801 if conf.env.ADDITIONAL_CFLAGS and conf.CHECK_CFLAGS(conf.env['ADDITIONAL_CFLAGS']):
802 conf.env['EXTRA_CFLAGS'].extend(conf.env['ADDITIONAL_CFLAGS'])
803 conf.add_os_flags('ADDITIONAL_LDFLAGS')
804 if conf.env.ADDITIONAL_LDFLAGS and conf.CHECK_LDFLAGS(conf.env['ADDITIONAL_LDFLAGS']):
805 conf.env['EXTRA_LDFLAGS'].extend(conf.env['ADDITIONAL_LDFLAGS'])
808 conf.write_config_header('default/config.h', top=True, remove=False)
810 conf.write_config_header(os.path.join(conf.variant, path), remove=False)
811 for key in conf.env.define_key:
812 conf.undefine(key, from_env=False)
813 conf.env.define_key = []
814 conf.SAMBA_CROSS_CHECK_COMPLETE()
818 def CONFIG_PATH(conf, name, default):
819 '''setup a configurable path'''
820 if not name in conf.env:
821 if default[0] == '/':
822 conf.env[name] = default
824 conf.env[name] = conf.env['PREFIX'] + default
827 def ADD_NAMED_CFLAGS(conf, name, flags, testflags=False, prereq_flags=[]):
828 '''add some CFLAGS to the command line
829 optionally set testflags to ensure all the flags work
831 prereq_flags = TO_LIST(prereq_flags)
834 for f in flags.split():
835 if CHECK_CFLAGS(conf, [f] + prereq_flags):
838 if not name in conf.env:
840 conf.env[name].extend(TO_LIST(flags))
843 def ADD_CFLAGS(conf, flags, testflags=False, prereq_flags=[]):
844 '''add some CFLAGS to the command line
845 optionally set testflags to ensure all the flags work
847 ADD_NAMED_CFLAGS(conf, 'EXTRA_CFLAGS', flags, testflags=testflags,
848 prereq_flags=prereq_flags)
851 def ADD_LDFLAGS(conf, flags, testflags=False):
852 '''add some LDFLAGS to the command line
853 optionally set testflags to ensure all the flags work
855 this will return the flags that are added, if any
859 for f in flags.split():
860 if CHECK_LDFLAGS(conf, f):
863 if not 'EXTRA_LDFLAGS' in conf.env:
864 conf.env['EXTRA_LDFLAGS'] = []
865 conf.env['EXTRA_LDFLAGS'].extend(TO_LIST(flags))
870 def ADD_EXTRA_INCLUDES(conf, includes):
871 '''add some extra include directories to all builds'''
872 if not 'EXTRA_INCLUDES' in conf.env:
873 conf.env['EXTRA_INCLUDES'] = []
874 conf.env['EXTRA_INCLUDES'].extend(TO_LIST(includes))
878 def CURRENT_CFLAGS(bld, target, cflags, allow_warnings=False, hide_symbols=False):
879 '''work out the current flags. local flags are added first'''
880 ret = TO_LIST(cflags)
881 if not 'EXTRA_CFLAGS' in bld.env:
884 list = bld.env['EXTRA_CFLAGS'];
886 if not allow_warnings and 'PICKY_CFLAGS' in bld.env:
887 list = bld.env['PICKY_CFLAGS'];
889 if hide_symbols and bld.env.HAVE_VISIBILITY_ATTR:
890 ret.append(bld.env.VISIBILITY_CFLAGS)
895 def CHECK_CC_ENV(conf):
896 """trim whitespaces from 'CC'.
897 The build farm sometimes puts a space at the start"""
898 if os.environ.get('CC'):
899 conf.env.CC = TO_LIST(os.environ.get('CC'))
903 def SETUP_CONFIGURE_CACHE(conf, enable):
904 '''enable/disable cache of configure results'''
906 # when -C is chosen, we will use a private cache and will
907 # not look into system includes. This roughtly matches what
908 # autoconf does with -C
909 cache_path = os.path.join(conf.bldnode.abspath(), '.confcache')
911 Options.cache_global = os.environ['WAFCACHE'] = cache_path
913 # when -C is not chosen we will not cache configure checks
914 # We set the recursion limit low to prevent waf from spending
915 # a lot of time on the signatures of the files.
916 Options.cache_global = os.environ['WAFCACHE'] = ''
917 preproc.recursion_limit = 1
918 # in either case we don't need to scan system includes
919 preproc.go_absolute = False
923 def SAMBA_CHECK_UNDEFINED_SYMBOL_FLAGS(conf):
924 # we don't want any libraries or modules to rely on runtime
925 # resolution of symbols
926 if not sys.platform.startswith("openbsd"):
927 conf.env.undefined_ldflags = conf.ADD_LDFLAGS('-Wl,-no-undefined', testflags=True)
929 if not sys.platform.startswith("openbsd") and conf.env.undefined_ignore_ldflags == []:
930 if conf.CHECK_LDFLAGS(['-undefined', 'dynamic_lookup']):
931 conf.env.undefined_ignore_ldflags = ['-undefined', 'dynamic_lookup']