* src/SDCCmain.c (setDefaultOptions, optionsTable[], parseCmdLine),

* src/SDCCmain.c (setDefaultOptions, optionsTable[], parseCmdLine),
* src/z80/main.c (_keywords[]),
* src/SDCCglobal.h (struct options),
* src/SDCC.y,
* src/SDCC.lex (isTargetKeyword, doPragma, pragma_tbl[]): new pragmas
to enable/disable SDCC and C99 extensions/keywords (std_c89, std_sdcc89,
std_c99, std_sdcc99). Also, equivalent command line options (--std-c89,
--std-sdcc89, --std-c99, --std-sdcc99). SDCC specific keywords are
always available in leading double underscore form. The C99 support is
mostly missing, but it's a start.
* support/regression/tests/bug-227710.c: fixed nonconforming use of
reserved identifier "__data".

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@3707 4a8a32a2-be11-0410-ad9d-d568d2c75423