mesa: add .mesa-install-links files to gitignore

Signed-off-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
diff --git a/.gitignore b/.gitignore
index 00e3ce3..21aa35c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -45,3 +45,4 @@
 .libs/
 Makefile
 Makefile.in
+.install-mesa-links