Include compiler_config_setting.bzl in release tarballs (#5715)

This should fix #5696.

Makefile.am

@@ -1087,6 +1087,7 @@ EXTRA_DIST = $(@DIST_LANG@_EXTRA_DIST)   \
   cmake/protoc.cmake                     \
   cmake/tests.cmake                      \
   cmake/version.rc.in                    \
+  compiler_config_setting.bzl            \
   editors/README.txt                     \
   editors/proto.vim                      \
   editors/protobuf-mode.el               \