1dnl Provide AC_USE_SYSTEM_EXTENSIONS for old autoconf machines. 2AC_DEFUN([ACX_USE_SYSTEM_EXTENSIONS],[ 3 ifdef([AC_USE_SYSTEM_EXTENSIONS],[ 4 AC_USE_SYSTEM_EXTENSIONS 5 ],[ 6 AC_BEFORE([$0], [AC_COMPILE_IFELSE]) 7 AC_BEFORE([$0], [AC_RUN_IFELSE]) 8 9 AC_REQUIRE([AC_GNU_SOURCE]) 10 AC_REQUIRE([AC_AIX]) 11 AC_REQUIRE([AC_MINIX]) 12 13 AH_VERBATIM([__EXTENSIONS__], 14[/* Enable extensions on Solaris. */ 15#ifndef __EXTENSIONS__ 16# undef __EXTENSIONS__ 17#endif 18#ifndef _POSIX_PTHREAD_SEMANTICS 19# undef _POSIX_PTHREAD_SEMANTICS 20#endif 21#ifndef _TANDEM_SOURCE 22# undef _TANDEM_SOURCE 23#endif]) 24 AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__], 25 [ac_cv_safe_to_define___extensions__], 26 [AC_COMPILE_IFELSE( 27 [AC_LANG_PROGRAM([ 28# define __EXTENSIONS__ 1 29 AC_INCLUDES_DEFAULT])], 30 [ac_cv_safe_to_define___extensions__=yes], 31 [ac_cv_safe_to_define___extensions__=no])]) 32 test $ac_cv_safe_to_define___extensions__ = yes && 33 AC_DEFINE([__EXTENSIONS__]) 34 AC_DEFINE([_POSIX_PTHREAD_SEMANTICS]) 35 AC_DEFINE([_TANDEM_SOURCE]) 36 ]) 37]) 38