https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67224
--- Comment #16 from Eric <ejolson at unr dot edu> --- With my second patch the command line must now include the options -finput-charset=UTF-8 -fextended-identifiers -fexec-charset=UTF-8 or otherwise C99 will also be used for the default execution character set. A better approach to maintain nearly 8-bit clean string literals by default might result from leaving the default input and execution characters sets as UTF-8 and setting the internal character set to C99 only when -fextended-identifiers is selected. Sorry for too many comments. I'll post a new patch when everything is ready and has been tested.