glapi: Build glapi_gentable.c only on Darwin

Removes the public symbol _glapi_create_table_from_handle from
libGL.so.1.2.0 on all platforms except Darwin.

Since the symbol is not used on other platforms it makes sense to
build glapi_gentable.c only on Darwin.

As a side effect it accelerates the build a bit and reduces the size
of libGL.so.1.2.0 as follows:

size lib/libGL.so.1.2.0 on my system shows
   text	   data	    bss	    dec	    hex	filename
 469211	  21848	   2720	 493779	  788d3	lib/libGL.so.1.2.0 before
 420988	  11240	   2720	 434948	  6a304	lib/libGL.so.1.2.0 after

A little bit of history:

_glapi_create_table_from_handle was introduced in

commit 85937f4c0d
Author: Jeremy Huddleston <jeremyhu@apple.com>
Date:   Thu Jun 9 16:59:49 2011 -0700

    glapi: Add API that can create a _glapi_table from a dlfcn handle

    Example usage:

    void *handle = dlopen(opengl_library_path, RTLD_LOCAL);
    struct _glapi_table *disp = _glapi_create_table_from_handle(handle,
"gl");

    Signed-off-by: Jeremy Huddleston <jeremyhu@apple.com>

and the only user in mesa was added in

commit f35913b96e
Author: Jeremy Huddleston <jeremyhu@apple.com>
Date:   Thu Jun 9 17:29:51 2011 -0700

    apple: Use _glapi_create_table_from_handle to initialize our
dispatch table

    Signed-off-by: Jeremy Huddleston <jeremyhu@apple.com>

gl_gentable.py was also used for XQuartz in xserver 1.11 - 1.14.

v2: Fix typos in commit message
    Add missing XORG_GLAPI_OUTPUTS += \ into src/mapi/glapi/gen/Makefile.am
    Add glapi_gentable.c to EXTRA_DIST for inclusion in the release
    tarball

v3: Fix commit message: s/gl_gentable.c/glapi_gentable.c/

Reported-by: Arlie Davis <arlied@google.com>
Cc: Jeremy Huddleston <jeremyhu@apple.com>
Signed-off-by: Andreas Boll <andreas.boll.dev@gmail.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>

src/mapi/Makefile.am

@@ -107,12 +107,16 @@ if HAVE_SPARC_ASM
 GLAPI_ASM_SOURCES = glapi/glapi_sparc.S
 endif
 
-glapi_libglapi_la_SOURCES = glapi/glapi_gentable.c
+glapi_libglapi_la_SOURCES =
 glapi_libglapi_la_CPPFLAGS = \
 	$(AM_CPPFLAGS) \
 	-I$(top_srcdir)/src/mapi/glapi \
 	-I$(top_srcdir)/src/mesa
 
+if HAVE_APPLEDRI
+glapi_libglapi_la_SOURCES += glapi/glapi_gentable.c
+endif
+
 if HAVE_SHARED_GLAPI
 glapi_libglapi_la_SOURCES += $(MAPI_BRIDGE_FILES) glapi/glapi_mapi_tmp.h
 glapi_libglapi_la_CPPFLAGS += \

src/mapi/glapi/gen/Makefile.am

@@ -27,8 +27,11 @@ MESA_GLAPI_OUTPUTS = \
 	$(MESA_GLAPI_DIR)/glapi_mapi_tmp.h \
 	$(MESA_GLAPI_DIR)/glprocs.h \
 	$(MESA_GLAPI_DIR)/glapitemp.h \
-	$(MESA_GLAPI_DIR)/glapitable.h \
-	$(MESA_GLAPI_DIR)/glapi_gentable.c
+	$(MESA_GLAPI_DIR)/glapitable.h
+
+if HAVE_APPLEDRI
+MESA_GLAPI_OUTPUTS += $(MESA_GLAPI_DIR)/glapi_gentable.c
+endif
 
 MESA_GLAPI_ASM_OUTPUTS =
 if HAVE_X86_ASM
@@ -57,6 +60,7 @@ BUILT_SOURCES = \
 	$(MESA_GLX_DIR)/indirect_size.c
 EXTRA_DIST= \
 	$(BUILT_SOURCES) \
+	$(MESA_GLAPI_DIR)/glapi_gentable.c \
 	$(MESA_GLAPI_DIR)/glapi_x86.S \
 	$(MESA_GLAPI_DIR)/glapi_x86-64.S \
 	$(MESA_GLAPI_DIR)/glapi_sparc.S \
@@ -88,8 +92,12 @@ XORG_GLAPI_DIR = $(XORG_BASE)/glx
 XORG_GLAPI_OUTPUTS = \
 	$(XORG_GLAPI_DIR)/glprocs.h \
 	$(XORG_GLAPI_DIR)/glapitable.h \
-	$(XORG_GLAPI_DIR)/dispatch.h \
+	$(XORG_GLAPI_DIR)/dispatch.h
+
+if HAVE_APPLEDRI
+XORG_GLAPI_OUTPUTS += \
 	$(XORG_GLAPI_DIR)/glapi_gentable.c
+endif
 
 XORG_OUTPUTS = \
 	$(XORG_GLAPI_OUTPUTS) \

src/mapi/glapi/glapi.h

@@ -158,8 +158,10 @@ _GLAPI_EXPORT const char *
 _glapi_get_proc_name(unsigned int offset);
 
 
+#ifdef GLX_USE_APPLEGL
 _GLAPI_EXPORT struct _glapi_table *
 _glapi_create_table_from_handle(void *handle, const char *symbol_prefix);
+#endif
 
 
 _GLAPI_EXPORT void