Allow external build flags

[skitt]

This change allows CFLAGS to be specified externally, and augmented with Free42's specific requirement.

It also applies CPPFLAGS which is used in a number of build systems (including Debian's, for "hardening" flags).

Signed-off-by: Stephen Kitt steve@sk2.org

[thomasokken]

I'm not sure I like the idea of making these changes (this and the other pull requests). I deliberately avoid creating or supporting packages for Linux package managers, because I don't want to take responsibility for downstream builds.

[skitt]

I don’t think any of these are specific to downstream builds; arguably this particular change is useful mostly for downstream builds, and few users building Free42 themselves would need it, but .desktop files and cross-compilation aren’t specific to any distribution.

However this particular change means that users can run commands like

make CFLAGS=-Os

(which breaks currently).

[skitt]

Of course this is your project, I don’t mind carrying these patches in Debian if you don’t want to make the changes upstream.

[skitt]

Thanks!