Re: adding specific C flags for a SINGLE source file

[Kevin P. Fleming]

Sander Niemeijer wrote:

> As a general remark, automake is not that clear in the precedence that 
> compiler flags take (will FOOFLAGS come before or after 
> AM_FOOFLAGS/target_FOOFLAGS) and if/how one would be able to overrule 
> these flags. Important is also to notice that CXXFLAGS/CFLAGS or 
> overruled by adding a new option at the end (e.g. '-O2 -O3' would end up 
> meaning '-O3'), but with include/library search paths in 
> CPPFLAGS/LDFLAGS it is exactly the other way around (e.g. '-Ifoo -Ibar' 
> ends up meaning '-Ifoo' when you have a foo/foo.h and bar/foo.h). I 
> think some notes about this in the documentation or FAQ would also be 
> very helpful.

Those precedence rules regarding -O, -I, -L and etc. have nothing to do 
with the autotools, and everything to do with your toolchain. It would 
not be practical to document any of this in the autotools docs (since 
toolchains differ), nor would it even be relevant.

In other words, you need to understand how your toolchain processes 
these flags before trying to understand how autotools usage of them will 
affect your project.