David A. Wheeler wrote:
> AC_PROG_CC_WARNINGS([low]) # off, low, medium, high; default medium
> and in gcc "medium" might map to "-Wall".
I'm afraid in practice things are not quite that simple.
The set of warning flags that are useful varies from project;
it's not a simple dial that one can turn from 1 to 10.
For example, GCC does something like the following,
if you configure --with-gcc-warnings:
* Enable all GCC warning flags that the current
compiler (whatever it is) supports.
* But disable -Wtautological-constant-out-of-range-compare,
-Wpointer-sign, -Wformat-extra-args, -Wunused-command-line-argument,
-Wunused-value if using clang.
* And disable -Wwrite-strings if using the Lucid or
Motif toolkits (since those old interfaces generate
too many warnings otherwise). And disable -Werror
while you're at it (ditto).
* Disable the following warnings on all platforms:
-Wsystem-headers, -Woverlength-strings, -Wlogical-op,
-Wformat-nonliteral, -Wvla, -Wnested-externs,
-Wswitch-default, -Winline, -Wjump-misses-init,
-Wstrict-overflow, -Wsync-nand, -Wunsafe-loop-optimizations,
-Wbad-function-cast, -Wshadow, -Wstack-protector,
-Wsuggest-attribute=pure, -Wmissing-field-initializers,
-Wsign-compare, -Wtype-limits, -Wunused-parameter.
* And if compiling the gnulib part of Emacs,
disable -Wunused-macros as well.
* Compile with _FORTIFY_SOURCE = 2 if optimizing, as
this enables some further compile-time warnings.
* Disable -pie, as -pie breaks Emacs's funky way
of saving its state.
The set of warnings options that other tools use is
neither a superset nor a subset of the options that
Emacs uses; there are simply too many knobs to turn.
If you're interested in pursuing this, I suggest that
you look at the configure.ac for Emacs, grep, coreutils,
diffutils, and tar, and look for some of the variations.
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