changeset 17474:88b6cb053cd7

warnings: minor optimization Paul Eggert suggested that expr is more efficient than echo|sed. * m4/warnings.m4 (gl_COMPILER_OPTION_IF): Use fewer processes. Signed-off-by: Eric Blake <eblake@redhat.com>
author Eric Blake <eblake@redhat.com>
date Thu, 15 Aug 2013 13:45:55 -0600
parents 1175d52f956a
children 9862f48da57d
files ChangeLog m4/warnings.m4
diffstat 2 files changed, 5 insertions(+), 2 deletions(-) [+]
line wrap: on
line diff
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2013-08-15  Eric Blake  <eblake@redhat.com>
 
+	warnings: minor optimization
+	* m4/warnings.m4 (gl_COMPILER_OPTION_IF): Use fewer processes.
+
 	warnings: check -Wfoo rather than -Wno-foo
 	* m4/warnings.m4 (gl_COMPILER_OPTION_IF): If name begins with
 	-Wno-, test if the compiler recognizes the positive form instead.
--- a/m4/warnings.m4
+++ b/m4/warnings.m4
@@ -1,4 +1,4 @@
-# warnings.m4 serial 9
+# warnings.m4 serial 10
 dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -29,7 +29,7 @@
   [m4_pushdef([gl_Positive], m4_bpatsubst([$1], [^-Wno-], [-W]))],
   [gl_positive="$1"
 case $gl_positive in
-  -Wno-*) gl_positive=`echo ".$gl_positive" | sed 's/^.//; s/^-Wno-/-W/'`;;
+  -Wno-*) gl_positive=-W`expr "X$gl_positive" : 'X-Wno-\(.*\)'` ;;
 esac
 m4_pushdef([gl_Positive], [$gl_positive])])dnl
 AC_CACHE_CHECK([whether _AC_LANG compiler handles $1], m4_defn([gl_Warn]), [