Test commits to all branches of portable.

Only test OpenBSD upstream on commits to master since that's what it
tracks.

.github/workflows/c-cpp.yml

@@ -2,10 +2,8 @@ name: C/C++ CI
 
 on:
   push:
-    branches: [ master, ci, V_9_0 ]
     paths: [ '**.c', '**.h', '**.m4', '**.sh', '.github/**', 'Makefile.in', 'configure.ac' ]
   pull_request:
-    branches: [ master ]
     paths: [ '**.c', '**.h', '**.m4', '**.sh', '.github/**', 'Makefile.in', 'configure.ac' ]
 
 jobs: