Use of __FILE__ macro prevents reproducible builds in appfw components

I had issues when I wanted to debug: the sources wasn't retrieved by debugger on my host when I defined the prefix in CMakeList.txt of the project.

I think that it is an issue in the build system.

It needs to be a trailing space with prepend.

I'd probably go for

as this is aligned with the debug-prefix-map statements.

Wrt location:

• to get started, we'd use it for the appfw and through the cmake module in the wgt's.

• we can also check if a global CFLAGS makes sense (need to check upstream master).
  .

... or write a small class that does the tweak on CFLAGS (gcc-tweaks.bbclass for example) then inherit from it in the needed recipes. This way, some logic can be added to be smarter if needed. And for apps, aglwgt.bbclass can also inherit from gcc-tweaks: so no need to update each app recipe.

The option must be prepended to be evaluated before -fdebug-prefix-map.
So the courrent definition should be

Where ${S} is yocto compatible.

An other option:

That produce p/a/t/h instead of ./p/a/t/h

I don't known where to put that line. Setting it globally is perhaps dangerous: does clang accept that option? (checking that ... No it doesn't!: clang-6.0: error: unknown argument: '-ffile-prefix-map=...').

So I propose to revert all what i pushed to quickly and to instead add the prepend option recipes by recipe.

yes, order is important: file-prefix-map overrides debug-prefix-map => debug opts must come last to be preserved.

DEBUG_PREFIX_MAP might also be the variable to tweak