whitelist the valid cases showing up
If an earlier version of clang is showing more cases (particularly
if they don't make sense), the re-enabling of the warning in
sys/unix/hints/include/compiler.2020 can be made clang-version
specific instead. I had no way to test earlier versions.
option ‘-Wimplicit’ is valid for C/ObjC but not for C++
option ‘-Wimplicit-function-declaration’ is valid for C/ObjC but not for C++
option ‘-Wimplicit-int’ is valid for C/ObjC but not for C++
option ‘-Wmissing-prototypes’ is valid for C/ObjC but not for C++
option ‘-Wmissing-parameter-type’ is valid for C/ObjC but not for C++
option ‘-Wold-style-definition’ is valid for C/ObjC but not for C++
option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
Whitelist all the verified existing triggers:
makedefs.c: In function ‘name_file’
attrib.c: one compiler balks at a ? b : c for fmtstring
cmd.c: In function ‘extcmd_via_menu’
cmd.c: In function ‘wiz_levltyp_legend’
do.c: In function ‘goto_level’
do_name.c: In function ‘coord_desc’
dungeon.c: In function ‘overview_stats’
eat.c: one compiler balks at a ? b : c for fmtstring
end.c: one compiler balks at a ? b : c for fmtstring
engrave.c: In function ‘engr_stats’
hack:c one compiler balks at a ? b : c for fmtstring
hacklib.c: one compiler balks at a ? b : c for fmtstring
insight.c: one compiler balks at a ? b : c for fmtstring
invent.c: In function ‘let_to_name’
light.c: In function ‘light_stats’
mhitm.c: In function ‘missmm’
options.c: In function ‘handler_symset’
options.c: In function ‘basic_menu_colors’
options.c: In function ‘optfn_o_autopickup_exceptions’
options.c: In function ‘optfn_o_menu_colors’
options.c: In function ‘optfn_o_message_types’
options.c: In function ‘optfn_o_status_cond’
options.c: In function ‘optfn_o_status_hilites’
options.c: In function ‘doset’
options.c: In function ‘doset_add_menu’
options.c: In function ‘show_menu_controls’
options.c: In function ‘handle_add_list_remove’
pager.c: In function ‘do_supplemental_info’
pager.c: In function ‘dohelp’
region.c: In function ‘region_stats’
rumors.c: sscanf usage
sounds.c: In function ‘domonnoise’
spell.c: In function ‘dospellmenu’
timeout.c: In function ‘timer_stats’
topten.c: In function ‘outentry’, fscanf, sscanf, fprintf usage
windows.c: In function ‘genl_status_update’
zap.c: one compiler balks at a ? b : c for fmtstring
win/curses/cursstat.c: In function ‘curses_status_update’
win/tty/wintty.c: In function ‘tty_status_update’
win/win32/mswproc.c: In function ‘mswin_status_update’
It turns out that macOS barked when a POP was issued without
a prior PUSH, so since the DISABLE_WARNING_CONDEXPR_IS_CONSTANT
expanded to an empty macro on that platform.
Include a corresponding
RESTORE_WARNING_CONDEXPR_IS_CONSTANT macro for use with that
particular warning.
Microsoft and other non-GNU compilers don't recognize gcc tricks
like /*NOTREACHED*/ to suppress individual warnings. clang recognizes most
of them because it tries to be gcc-compatible. Because of that, a lot of
potentially useful warnings have had to be completely suppressed in the
past in all source files when using the non-gcc compatible compilers.
Now that the code is C99, take advantage of a way to suppress warnings for
individual functions, a big step up from suppressing the warnings
altogether.
Unfortunately, it does require a bit of ugliness caused by the
insertion of some macros in a few spots, but I'm not aware of
a cleaner alternative that still allows warnings to be enabled
in general, while suppressing a warning for known white-listed
instances.
Prior to the warning-tiggering function, place whichever one of
the following is needed to suppress the warning being encountered:
DISABLE_WARNING_UNREACHABLE_CODE
DISABLE_WARNING_CONDEXPR_IS_CONSTANT
After the warning-triggering function, place this:
RESTORE_WARNINGS
Under the hood, the compiler-appropriate warning-disabling
mechanics involve the use of C99 _Pragma, which can be used
in macros.
For unrecognized or inappropriate compilers, or if
DISABLE_WARNING_PRAGMAS is defined, the macros expand
to nothing.
