Compiler check and extra args should always override

We want compiler check arguments (-O0, -fpermissive, etc) to override
all other arguments, and we want extra_args passed in by the build file
to always override everything.

To do this properly, we must split include arguments out, append them
first, append all other arguments as usual, and then append the rest.

As part of this, we also add the compiler check flags to the
cc.compiles() and cc.links() helper functions since they also most
likely need them.

Also includes a unit test for all this.

0 files changed, 0 insertions, 0 deletions