nanosleep: Avoid guessing wrong when cross-compiling to Linux.

[gnulib.git] / m4 / warnings.m4

diff --git a/m4/warnings.m4 b/m4/warnings.m4
index 634b183..c14c480 100644 (file)
--- a/m4/warnings.m4
+++ b/m4/warnings.m4
@@ -1,26 +1,11 @@
-# warnings.m4 serial 1
-dnl Copyright (C) 2008 Free Software Foundation, Inc.
+# warnings.m4 serial 6
+dnl Copyright (C) 2008-2012 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
 dnl From Simon Josefsson
 
-# gl_WARN_INIT
-# Initializes WARN_CFLAGS variable.
-AC_DEFUN([gl_WARN_INIT],
-[
-  AC_ARG_VAR(WARN_CFLAGS, [C compiler warning flags])
-])
-
-# gl_AS_VAR_IF(VAR, VALUE, [IF-MATCH], [IF-NOT-MATCH])
-# ----------------------------------------------------
-# Provide the functionality of AS_VAR_IF if Autoconf does not have it.
-m4_ifdef([AS_VAR_IF],
-[m4_copy([AS_VAR_IF], [gl_AS_VAR_IF])],
-[m4_define([gl_AS_VAR_IF],
-[AS_IF([test x"AS_VAR_GET([$1])" = x""$2], [$3], [$4])])])
-
 # gl_AS_VAR_APPEND(VAR, VALUE)
 # ----------------------------
 # Provide the functionality of AS_VAR_APPEND if Autoconf does not have it.
@@ -29,22 +14,29 @@ m4_ifdef([AS_VAR_APPEND],
 [m4_define([gl_AS_VAR_APPEND],
 [AS_VAR_SET([$1], [AS_VAR_GET([$1])$2])])])
 
+
 # gl_WARN_ADD(PARAMETER, [VARIABLE = WARN_CFLAGS])
 # ------------------------------------------------
 # Adds parameter to WARN_CFLAGS if the compiler supports it.  For example,
 # gl_WARN_ADD([-Wparentheses]).
+#
+# If VARIABLE is a variable name, AC_SUBST it.
 AC_DEFUN([gl_WARN_ADD],
-[AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_$1])dnl
-AC_CACHE_CHECK([whether compiler handles $1], [gl_Warn], [
-  save_CFLAGS="$CFLAGS"
-  CFLAGS="${CFLAGS} $1"
-  AC_PREPROC_IFELSE([AC_LANG_PROGRAM([])],
-                    [AS_VAR_SET([gl_Warn], [yes])],
-                   [AS_VAR_SET([gl_Warn], [no])])
-  CFLAGS="$save_CFLAGS"
+dnl FIXME: gl_Warn must be used unquoted until we can assume
+dnl autoconf 2.64 or newer.
+[AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_[]_AC_LANG_ABBREV[]_$1])dnl
+AS_VAR_PUSHDEF([gl_Flags], [_AC_LANG_PREFIX[]FLAGS])dnl
+AC_CACHE_CHECK([whether _AC_LANG compiler handles $1], m4_defn([gl_Warn]), [
+  gl_save_compiler_FLAGS="$gl_Flags"
+  gl_Flags="$gl_Flags $1"
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([])],
+                    [AS_VAR_SET(gl_Warn, [yes])],
+                    [AS_VAR_SET(gl_Warn, [no])])
+  gl_Flags="$gl_save_compiler_FLAGS"
 ])
-AS_VAR_PUSHDEF([gl_Flags], m4_if([$2], [], [[WARN_CFLAGS]], [[$2]]))dnl
-gl_AS_VAR_IF([gl_Warn], [yes], [gl_AS_VAR_APPEND([gl_Flags], [" $1"])])
+AS_VAR_IF(gl_Warn, [yes],
+  [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_CFLAGS]], [[$2]]), [" $1"])])
 AS_VAR_POPDEF([gl_Flags])dnl
 AS_VAR_POPDEF([gl_Warn])dnl
+m4_ifval([$2], [AS_LITERAL_IF([$2], [AC_SUBST([$2])], [])])dnl
 ])