dnl CF_CHECK_ENVIRON version: 3 updated: 2010/05/26 16:44:57
dnl ----------------
dnl Check for data that is usually declared in <unistd.h>, e.g., the 'environ'
dnl variable.  Define a DECL_xxx symbol if we must declare it ourselves.
dnl
dnl $1 = the name to check
dnl $2 = the assumed type
AC_DEFUN([CF_CHECK_ENVIRON],
[
AC_CACHE_CHECK(if external $1 is declared, cf_cv_dcl_$1,[
    AC_TRY_COMPILE([
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <unistd.h> ],
    ifelse([$2],,int,[$2]) x = (ifelse([$2],,int,[$2])) $1,
    [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
