Update top-level .gitignore.
treef620d9c07d2d80f8017936e82a67555bcfd3a8c8
-rw-r--r-- 24 .gitignore
-rw-r--r-- 1155 Makefile
-rw-r--r-- 1038 Makefile.top
-rwxr-xr-x 165 mkdeps
drwxr-xr-x - src
drwxr-xr-x - tests