dri/osmesa: automake: include builddir prior to srcdir

Analogous to previous commit.

Cc: "12.0 13.0" <mesa-dev@lists.freedesktop.org>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
(cherry picked from commit 6ba96bdcabc4c9c89827603907aba1b7dd5e9972)
diff --git a/src/mesa/drivers/osmesa/Makefile.am b/src/mesa/drivers/osmesa/Makefile.am
index 5525687..2c8d466 100644
--- a/src/mesa/drivers/osmesa/Makefile.am
+++ b/src/mesa/drivers/osmesa/Makefile.am
@@ -28,8 +28,8 @@
 	-I$(top_srcdir)/src \
 	-I$(top_srcdir)/src/gallium/include \
 	-I$(top_srcdir)/src/gallium/auxiliary \
-	-I$(top_srcdir)/src/mapi \
 	-I$(top_builddir)/src/mapi \
+	-I$(top_srcdir)/src/mapi \
 	-I$(top_srcdir)/src/mesa/ \
 	$(DEFINES)
 AM_CFLAGS = $(PTHREAD_CFLAGS) \