dri: Reuse dri_test.c for stub glapi symbols for unit testing.

This file is used to provide stubs for the link test in gallium dri drivers.
But the same stubs without the main can be used for making unit tests for code
in a dri driver.

Acked-by: Paul Berry <stereotype441@gmail.com>

src/mesa/drivers/dri/common/Makefile.am

@@ -28,11 +28,17 @@ AM_CFLAGS = \
 	$(API_DEFINES) \
 	$(LIBDRM_CFLAGS)
 
-noinst_LTLIBRARIES = libdricommon.la
+noinst_LTLIBRARIES = \
+	libdricommon.la \
+	libdri_test_stubs.la
 
 libdricommon_la_SOURCES = \
 	utils.c \
 	dri_util.c \
 	xmlconfig.c
 
+libdri_test_stubs_la_SOURCES = \
+	dri_test.c
+libdri_test_stubs_la_CFLAGS = $(AM_CFLAGS) -DNO_MAIN
+
 sysconf_DATA = drirc

src/mesa/drivers/dri/common/dri_test.c

@@ -82,8 +82,10 @@ _glthread_GetID(void)
    return 0;
 }
 
+#ifndef NO_MAIN
 int main(int argc, char** argv)
 {
    void* p = __driDriverExtensions;
    return (int)(unsigned long)p;
 }
+#endif