1 files changed, 19 insertions, 1 deletions

diff --git a/aclocal.m4 b/aclocal.m4
index 83b241f7b..9bdea5ec2 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1,8 +1,26 @@
-dnl $Id: aclocal.m4,v 1.7 2011/05/05 03:48:37 djm Exp $
+dnl $Id: aclocal.m4,v 1.8 2011/05/20 01:45:25 djm Exp $
 dnl
 dnl OpenSSH-specific autoconf macros
 dnl
 
+dnl OSSH_CHECK_CFLAG_COMPILE(check_flag[, define_flag])
+dnl Check that $CC accepts a flag 'check_flag'. If it is supported append
+dnl 'define_flag' to $CFLAGS. If 'define_flag' is not specified, then append
+dnl 'check_flag'.
+AC_DEFUN([OSSH_CHECK_CFLAG_COMPILE], [{
+        AC_MSG_CHECKING([if $CC supports $1])
+        saved_CFLAGS="$CFLAGS"
+        CFLAGS="$CFLAGS $1"
+        _define_flag="$2"
+        test "x$_define_flag" = "x" && _define_flag="$1"
+        AC_COMPILE_IFELSE([AC_LANG_SOURCE([[int main(void) { return 0; }]])],
+                [ AC_MSG_RESULT([yes])
+                  CFLAGS="$saved_CFLAGS $_define_flag"],
+                [ AC_MSG_RESULT([no])
+                  CFLAGS="$saved_CFLAGS" ]
+        )
+}])
+
 
 dnl OSSH_CHECK_HEADER_FOR_FIELD(field, header, symbol)
 dnl Does AC_EGREP_HEADER on 'header' for the string 'field'