re PR other/55312 (libbacktrace doesn't honor --disable-werror)

	PR other/55312
	* configure.ac: Only add -Werror if building a target library.

From-SVN: r193485

libbacktrace/ChangeLog

+2012-11-13  Ian Lance Taylor  <iant@google.com>
+
+	PR other/55312
+	* configure.ac: Only add -Werror if building a target library.
+
 2012-11-12  Ian Lance Taylor  <iant@google.com>
 	    Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 	    Gerald Pfeifer  <gerald@pfeifer.com>

libbacktrace/configure

@@ -11575,7 +11575,7 @@ fi
 CFLAGS="$save_CFLAGS"
 
 
-if test "x$GCC" = "xyes"; then
+if test -n "${with_target_subdir}"; then
   WARN_FLAGS="$WARN_FLAGS -Werror"
 fi
 

libbacktrace/configure.ac

@@ -120,7 +120,7 @@ ACX_PROG_CC_WARNING_OPTS([-W -Wall -Wwrite-strings -Wstrict-prototypes \
 			  -Wmissing-format-attribute -Wcast-qual],
 			  [WARN_FLAGS])
 
-if test "x$GCC" = "xyes"; then
+if test -n "${with_target_subdir}"; then
   WARN_FLAGS="$WARN_FLAGS -Werror"
 fi