Fix Savannah bug #34832 with unused TLS attributes.

w32/subproc/w32err.c (map_windows32_error_to_string) [_MSC_VER]:
 Don't use TLS storage for szMessageBuffer.  Ifdef away special
 code for handling Winsock error codes.  Make the function return a
 `const char *'.  Suggested by Ozkan Sezer.  Fixes Savannah bug #34832.

ChangeLog

@@ -1,3 +1,10 @@
+2012-02-03  Eli Zaretskii  <eliz@gnu.org>
+
+	* w32/subproc/w32err.c (map_windows32_error_to_string) [_MSC_VER]:
+	Don't use TLS storage for szMessageBuffer.  Ifdef away special
+	code for handling Winsock error codes.  Make the function return a
+	`const char *'.  Suggested by Ozkan Sezer.  Fixes Savannah bug #34832.
+
 2012-01-29  Paul Smith  <psmith@gnu.org>
 
 	* gmk-default.scm (to-string-maybe): Variables map to empty strings.

w32/include/w32err.h

@@ -22,6 +22,6 @@ this program.  If not, see <http://www.gnu.org/licenses/>.  */
 #define EXTERN_DECL(entry, args) entry args
 #endif
 
-EXTERN_DECL(char * map_windows32_error_to_string, (DWORD error));
+EXTERN_DECL(const char * map_windows32_error_to_string, (DWORD error));
 
 #endif /* !_W32ERR_H */

w32/subproc/w32err.c

@@ -15,7 +15,9 @@ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
 You should have received a copy of the GNU General Public License along with
 this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
+#include <stdlib.h>
 #include <windows.h>
+#include "make.h"
 #include "w32err.h"
 
 /*
@@ -26,14 +28,24 @@ this program.  If not, see <http://www.gnu.org/licenses/>.  */
  * Notes/Dependencies:  I got this from
  *      comp.os.ms-windows.programmer.win32
  */
-char *
+const char *
 map_windows32_error_to_string (DWORD ercode) {
-/* __declspec (thread) necessary if you will use multiple threads on MSVC */
+/*
-#ifdef _MSC_VER
+ * We used to have an MSVC-specific `__declspec (thread)' qualifier
-__declspec (thread) static char szMessageBuffer[128];
+ * here, with the following comment:
-#else
+ *
+ * __declspec (thread) necessary if you will use multiple threads on MSVC
+ *
+ * However, Make was never multithreaded on Windows (except when
+ * Ctrl-C is hit, in which case the main thread is stopped
+ * immediately, so it doesn't matter in this context).  The functions
+ * on sub_proc.c that started and stopped additional threads were
+ * never used, and are now #ifdef'ed away.  Until we need more than
+ * one thread, we have no problems with the following buffer being
+ * static.  (If and when we do need it to be in thread-local storage,
+ * the corresponding GCC qualifier is `__thread'.)
+ */
     static char szMessageBuffer[128];
-#endif
 	/* Fill message buffer with a default message in
 	 * case FormatMessage fails
 	 */
@@ -43,6 +55,7 @@ static char szMessageBuffer[128];
 	 *  Special code for winsock error handling.
 	 */
 	if (ercode > WSABASEERR) {
+#if 0
 		HMODULE hModule = GetModuleHandle("wsock32");
 		if (hModule != NULL) {
 			FormatMessage(FORMAT_MESSAGE_FROM_HMODULE,
@@ -54,6 +67,9 @@ static char szMessageBuffer[128];
 				NULL);
 			FreeLibrary(hModule);
 		}
+#else
+		fatal(NILF, szMessageBuffer);
+#endif
 	} else {
 		/*
 		 *  Default system message handling