configure: Disable default CFLAGS from AC_PROG_CC

[cole-miller]

AC_PROG_CC adds some default compiler flags unless you tell it not to:

If using the GNU C compiler, set shell variable GCC to ‘yes’. If output variable CFLAGS was not already set, set it to -g -O2 for the GNU C compiler (-O2 on systems where GCC does not accept -g), or -g for other compilers.

(Source.)

Also tweak DEBUG_ENABLED handling in Makefile.am: we always pass -g3 in the basic CFLAGS set from configure.ac, so no point adding it again there. Instead, pass -O0, which should be the default but here serves as a kind of documentation.

Credit to @letFunny for noticing that -O2 was getting passed to gcc even for builds configured with --enable-debug.

Signed-off-by: Cole Miller cole.miller@canonical.com

[cole-miller]

FYI @freeekanayaka

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.43%. Comparing base (cb65db7) to head (334e23e).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #651      +/-   ##
==========================================
- Coverage   80.57%   77.43%   -3.14%     
==========================================
  Files         196      196              
  Lines       28301    27233    -1068     
  Branches     5300     5492     +192     
==========================================
- Hits        22803    21089    -1714     
- Misses       3767     4383     +616     
- Partials     1731     1761      +30     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[letFunny]

Thanks

[cole-miller]

I've confirmed locally that this results in the intended CFLAGS being placed into the generated Makefile.