Quoting julvr <[email protected]>:
OK, after some more investigation, it looks like this boils down to whether EXTRA_CFLAGS is recursivly expanded or simply expanded... But again, I'm a bit out of my depth in this: In the kernel, there are several places where you see EXTRA_CFLAGS = xxx and others where you see EXTRA_CFLAGS := xxxx (usb/storage/Makefile and fs/ntfs/Makefile for example)and then a whole lot of += modifiers... So if you have both of these in your make-path, which one takes precedence? If I include a single file that has a :=, does that effect all other files, or just sub-makefiles of it? Does 'export' have any effect on this
As best as I recall, and I'm away from my regular system so I don't have access to the source ATM, the last one seen takes precedence.
So, in a context where the last assignment was "=", the "+=" is interpreted as a recursive expansion. In a context where the last assignment was ":=", the "+=" is interpreted as a simple expansion. If there was no prior non-append assignment, the default is recursive expansion.
Export has no impact on this. _______________________________________________ Help-make mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-make
