warnings.m4: check the compiler, not the preprocessor

[gnulib.git] / m4 / threadlib.m4

diff --git a/m4/threadlib.m4 b/m4/threadlib.m4
index 01ee9dd..9cedb67 100644 (file)
--- a/m4/threadlib.m4
+++ b/m4/threadlib.m4
@@ -1,5 +1,5 @@
-# threadlib.m4 serial 6 (gettext-0.18.2)
-dnl Copyright (C) 2005-2010 Free Software Foundation, Inc.
+# threadlib.m4 serial 9 (gettext-0.18.2)
+dnl Copyright (C) 2005-2012 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.
@@ -9,8 +9,13 @@ dnl From Bruno Haible.
 dnl gl_THREADLIB
 dnl ------------
 dnl Tests for a multithreading library to be used.
+dnl If the configure.ac contains a definition of the gl_THREADLIB_DEFAULT_NO
+dnl (it must be placed before the invocation of gl_THREADLIB_EARLY!), then the
+dnl default is 'no', otherwise it is system dependent. In both cases, the user
+dnl can change the choice through the options --enable-threads=choice or
+dnl --disable-threads.
 dnl Defines at most one of the macros USE_POSIX_THREADS, USE_SOLARIS_THREADS,
-dnl USE_PTH_THREADS, USE_WIN32_THREADS
+dnl USE_PTH_THREADS, USE_WINDOWS_THREADS
 dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
 dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with
 dnl libtool).
@@ -44,10 +49,12 @@ AC_DEFUN([gl_THREADLIB_EARLY_BODY],
     [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
     [AC_REQUIRE([AC_GNU_SOURCE])])
   dnl Check for multithreading.
-  m4_divert_text([DEFAULTS], [gl_use_threads_default=])
+  m4_ifdef([gl_THREADLIB_DEFAULT_NO],
+    [m4_divert_text([DEFAULTS], [gl_use_threads_default=no])],
+    [m4_divert_text([DEFAULTS], [gl_use_threads_default=])])
   AC_ARG_ENABLE([threads],
-AC_HELP_STRING([--enable-threads={posix|solaris|pth|win32}], [specify multithreading API])
-AC_HELP_STRING([--disable-threads], [build without multithread safety]),
+AC_HELP_STRING([--enable-threads={posix|solaris|pth|windows}], [specify multithreading API])m4_ifdef([gl_THREADLIB_DEFAULT_NO], [], [
+AC_HELP_STRING([--disable-threads], [build without multithread safety])]),
     [gl_use_threads=$enableval],
     [if test -n "$gl_use_threads_default"; then
        gl_use_threads="$gl_use_threads_default"
@@ -120,13 +127,16 @@ AC_DEFUN([gl_THREADLIB_BODY],
        if test $gl_cv_have_weak = maybe; then
          dnl Second, test whether it actually works. On Cygwin 1.7.2, with
          dnl gcc 4.3, symbols declared weak always evaluate to the address 0.
-         AC_TRY_RUN([
+         AC_RUN_IFELSE(
+           [AC_LANG_SOURCE([[
 #include <stdio.h>
 #pragma weak fputs
 int main ()
 {
   return (fputs == NULL);
-}], [gl_cv_have_weak=yes], [gl_cv_have_weak=no],
+}]])],
+           [gl_cv_have_weak=yes],
+           [gl_cv_have_weak=no],
            [dnl When cross-compiling, assume that only ELF platforms support
             dnl weak symbols.
             AC_EGREP_CPP([Extensible Linking Format],
@@ -240,7 +250,7 @@ int main ()
       AC_LIB_LINKFLAGS([pth])
       gl_have_pth=
       gl_save_LIBS="$LIBS"
-      LIBS="$LIBS -lpth"
+      LIBS="$LIBS $LIBPTH"
       AC_LINK_IFELSE(
         [AC_LANG_PROGRAM([[#include <pth.h>]], [[pth_self();]])],
         [gl_have_pth=yes])
@@ -266,17 +276,19 @@ int main ()
       fi
     fi
     if test -z "$gl_have_pthread"; then
-      if test "$gl_use_threads" = yes || test "$gl_use_threads" = win32; then
-        if { case "$host_os" in
-               mingw*) true;;
-               *) false;;
-             esac
-           }; then
-          gl_threads_api=win32
-          AC_DEFINE([USE_WIN32_THREADS], [1],
-            [Define if the Win32 multithreading API can be used.])
-        fi
-      fi
+      case "$gl_use_threads" in
+        yes | windows | win32) # The 'win32' is for backward compatibility.
+          if { case "$host_os" in
+                 mingw*) true;;
+                 *) false;;
+               esac
+             }; then
+            gl_threads_api=windows
+            AC_DEFINE([USE_WINDOWS_THREADS], [1],
+              [Define if the native Windows multithreading API can be used.])
+          fi
+          ;;
+      esac
     fi
   fi
   AC_MSG_CHECKING([for multithread API to use])
@@ -348,7 +360,7 @@ dnl Cygwin            posix       -lpthread       Y      OK
 dnl
 dnl Any of the above  pth         -lpth                  0.0
 dnl
-dnl Mingw             win32                       N      OK
+dnl Mingw             windows                     N      OK
 dnl
 dnl BeOS 5            --
 dnl