invert gthread-impl includes

configure.ac defined G_THREAD_SOURCE and gthread-impl would #include it.

Instead, since we only have two thread implementations now, and since we
always use the Windows one only on Windows, move the logic to the
Makefile, predicated on 'if OS_WIN32'.  Then have the chosen backend do
the #include "gthread-impl.c" from there.

Remove the G_THREAD_SOURCE define from configure.ac.

configure.ac

@@ -2419,8 +2419,6 @@ case $host in
     ;;
 esac
 
-AC_DEFINE_UNQUOTED(G_THREAD_SOURCE,"gthread-$have_threads.c",
-		   [Source file containing thread implementation])
 AC_SUBST(G_THREAD_CFLAGS)
 AC_SUBST(G_THREAD_LIBS)
 AC_SUBST(G_THREAD_LIBS_FOR_GTHREAD)

gthread/Makefile.am

@@ -66,7 +66,11 @@ gthread_win32_res = gthread-win32-res.o
 gthread_win32_res_ldflag = -Wl,$(gthread_win32_res)
 endif
 
-libgthread_2_0_la_SOURCES = gthread-impl.c
+if OS_WIN32
+libgthread_2_0_la_SOURCES = gthread-win32.c
+else
+libgthread_2_0_la_SOURCES = gthread-posix.c
+endif
 libgthread_2_0_la_LDFLAGS = $(GLIB_LINK_FLAGS) \
 	$(gthread_win32_res_ldflag) \
 	-version-info $(LT_CURRENT):$(LT_REVISION):$(LT_AGE) \

gthread/gthread-impl.c

@@ -31,13 +31,6 @@
  * MT safe
  */
 
-#include "config.h"
-
-#include "glib.h"
-#include "gthreadprivate.h"
-
-#include G_THREAD_SOURCE
-
 void
 g_thread_init (GThreadFunctions *init)
 {

gthread/gthread-posix.c

@@ -33,6 +33,9 @@
 
 #include "config.h"
 
+#include "glib.h"
+#include "gthreadprivate.h"
+
 #include <pthread.h>
 #include <errno.h>
 #include <stdlib.h>
@@ -402,3 +405,5 @@ static GThreadFunctions g_thread_functions_for_glib_use_default =
   g_thread_self_posix_impl,
   g_thread_equal_posix_impl
 };
+
+#include "gthread-impl.c"

gthread/gthread-win32.c

@@ -35,6 +35,7 @@
 #include "config.h"
 
 #include "glib.h"
+#include "gthreadprivate.h"
 
 #define STRICT
 #define _WIN32_WINDOWS 0x0401 /* to get IsDebuggerPresent */
@@ -558,3 +559,5 @@ g_thread_impl_init ()
 			 (g_cond_event_tls = TlsAlloc ()));
   InitializeCriticalSection (&g_thread_global_spinlock);
 }
+
+#include "gthread-impl.c"