1dnl ###################################################################### 2dnl find if "extern char *optarg" exists in headers 3AC_DEFUN([AMU_EXTERN_OPTARG], 4[ 5AC_CACHE_CHECK(if external definition for optarg[] exists, 6ac_cv_extern_optarg, 7[ 8# try to compile program that uses the variable 9AC_TRY_COMPILE( 10[ 11#ifdef HAVE_STDIO_H 12# include <stdio.h> 13#endif /* HAVE_STDIO_H */ 14#ifdef HAVE_UNISTD_H 15# include <unistd.h> 16#endif /* HAVE_UNISTD_H */ 17#ifdef HAVE_STDLIB_H 18# include <stdlib.h> 19#endif /* HAVE_STDLIB_H */ 20#ifdef HAVE_SYS_ERRNO_H 21# include <sys/errno.h> 22#endif /* HAVE_SYS_ERRNO_H */ 23#ifdef HAVE_ERRNO_H 24# include <errno.h> 25#endif /* HAVE_ERRNO_H */ 26], 27[ 28char *cp = optarg; 29], ac_cv_extern_optarg=yes, ac_cv_extern_optarg=no) 30]) 31if test "$ac_cv_extern_optarg" = yes 32then 33 AC_DEFINE(HAVE_EXTERN_OPTARG) 34fi 35]) 36dnl ====================================================================== 37