CFE-3629 - just poking around

[btriller]

Set CFLAGS before AC_PROG_CC as it might add -g/-O options if CFLAGS is unset.
Don't add CFLAGS to CORE_FLAGS because I don't know, but maybe CFLAGS is populated otherwise.

[olehermanse]

@btriller Why did you close this? IIRC, the change looked reasonable, but more work was needed to fix the failing tests(?)

[btriller]

@btriller Why did you close this? IIRC, the change looked reasonable, but more work was needed to fix the failing tests(?)

I looked further into it on macOS (with clang). With -Wall -Werror, there were many errors about redefinition that I wasn't sure I'm able to resolve it. IIRC on Linux with gcc and, for starters, more ifdefs in libcfecompat, it looked better.

[olehermanse]

@btriller Thanks for working on this. We're a bit busy with getting the releases out, but I'll get back to reviewing the PR shortly after that :)

[larsewi]

Generally we should not really touch CFLAGS at all. This variable is intended for the end user only. People familiar with autotools would expect the AC_PROG_CC defaults. Anything else would come as a surprise. However, we do already touch them. Hence, not touching them would probably come as a surprise for people familiar with compiling CFEngine.

In this thread it is suggested to set : ${CFLAGS=""} to empty before AC_PROG_CC if not already set by the user. This way we could control the optimization flags through AM_CFLAGS which would be the proper way to set our own flags. Do you want to try this out? Or do you want us to take a look at it?