+# Remember that #undef in AH_VERBATIM gets replaced with #define by
+# AC_DEFINE. The goal here is to define all known feature-enabling
+# macros, then, if reports of conflicts are made, disable macros that
+# cause problems on some platforms (such as __EXTENSIONS__).
+AC_DEFUN([AC_USE_SYSTEM_EXTENSIONS],
+[AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
+AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
+
+ AC_CHECK_HEADER([minix/config.h], [MINIX=yes], [MINIX=])
+ if test "$MINIX" = yes; then
+ AC_DEFINE([_POSIX_SOURCE], [1],
+ [Define to 1 if you need to in order for `stat' and other
+ things to work.])
+ AC_DEFINE([_POSIX_1_SOURCE], [2],
+ [Define to 2 if the system does not provide POSIX.1 features
+ except with this defined.])
+ AC_DEFINE([_MINIX], [1],
+ [Define to 1 if on MINIX.])
+ fi
+