dnl CF_CHECK_ERRNO version: 13 updated: 2020/03/10 18:53:47
dnl --------------
dnl Check for data that is usually declared in <stdio.h> or <errno.h>, e.g.,
dnl the 'errno' variable.  Define a DECL_xxx symbol if we must declare it
dnl ourselves.
dnl
dnl $1 = the name to check
dnl $2 = the assumed type
AC_DEFUN([CF_CHECK_ERRNO],
[
AC_CACHE_CHECK(if external $1 is declared, cf_cv_dcl_$1,[
	AC_TRY_COMPILE([
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <stdio.h>
#include <sys/types.h>
#include <errno.h> ],
	ifelse([$2],,int,[$2]) x = (ifelse([$2],,int,[$2])) $1; (void)x,
	[cf_cv_dcl_$1=yes],
	[cf_cv_dcl_$1=no])
])

if test "$cf_cv_dcl_$1" = no ; then
	CF_UPPER(cf_result,decl_$1)
	AC_DEFINE_UNQUOTED($cf_result)
fi

# It's possible (for near-UNIX clones) that the data doesn't exist
CF_CHECK_EXTERN_DATA($1,ifelse([$2],,int,[$2]))
])dnl
