test harness: improve catching of usage errors in script 'test-driver'

[platform/upstream/automake.git] / m4 / ar-lib.m4

diff --git a/m4/ar-lib.m4 b/m4/ar-lib.m4
index 470def4..58726d0 100644 (file)
--- a/m4/ar-lib.m4
+++ b/m4/ar-lib.m4
@@ -1,12 +1,10 @@
 ##                                                          -*- Autoconf -*-
-# Copyright (C) 2011-2012 Free Software Foundation, Inc.
+# Copyright (C) 2011-2013 Free Software Foundation, Inc.
 #
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
-# serial 1
-
 # AM_PROG_AR([ACT-IF-FAIL])
 # -------------------------
 # Try to determine the archiver interface, and trigger the ar-lib wrapper
@@ -21,7 +19,8 @@ AC_CHECK_TOOLS([AR], [ar lib "link -lib"], [false])
 : ${AR=ar}
 
 AC_CACHE_CHECK([the archiver ($AR) interface], [am_cv_ar_interface],
-  [am_cv_ar_interface=ar
+  [AC_LANG_PUSH([C])
+   am_cv_ar_interface=ar
    AC_COMPILE_IFELSE([AC_LANG_SOURCE([[int some_variable = 0;]])],
      [am_ar_try='$AR cru libconftest.a conftest.$ac_objext >&AS_MESSAGE_LOG_FD'
       AC_TRY_EVAL([am_ar_try])
@@ -38,7 +37,7 @@ AC_CACHE_CHECK([the archiver ($AR) interface], [am_cv_ar_interface],
       fi
       rm -f conftest.lib libconftest.a
      ])
-   ])
+   AC_LANG_POP([C])])
 
 case $am_cv_ar_interface in
 ar)