mesa: Convert gl.pc to be generated by configure.
This saves a step of mashing variables around in our Makefile.
diff --git a/configure.ac b/configure.ac
index 532feaa..a5df38a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2185,7 +2185,8 @@
src/mesa/drivers/dri/r200/Makefile
src/mesa/drivers/dri/radeon/Makefile
src/mesa/drivers/dri/swrast/Makefile
- src/mesa/drivers/x11/Makefile])
+ src/mesa/drivers/x11/Makefile
+ src/mesa/gl.pc])
dnl Sort the dirs alphabetically
GALLIUM_TARGET_DIRS=`echo $GALLIUM_TARGET_DIRS|tr " " "\n"|sort -u|tr "\n" " "`