Fix -Wimplicit-fallthrough warnings in regcomp.c


Fix -Wimplicit-fallthrough warnings in regcomp.c

Since clang does not support comment style fallthrough annotations
these should be switched.

Reviewers: aaron.ballman, nickdesaulniers, xbolva00

Reviewed By: aaron.ballman, nickdesaulniers, xbolva00

Subscribers: xbolva00, nickdesaulniers, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66487

Event Timeline

This broke several of the bots (eg). It seems any of the __has_cpp_attribute checks that have a namespace qualified attributes will need to be guarded by a if defined(__cplusplus) if we are including the header in a C file.