Makefiles: Support specifying CFLAGS on the command line

This patch makes the liburing build work as expected for e.g. the following
command:

make CFLAGS=-m32

and avoids that the build fails as follows for the above command:

make[1]: Entering directory 'liburing/test'
cc -m32 -o poll poll.c -luring
/usr/bin/ld: cannot find -luring
collect2: error: ld returned 1 exit status
Makefile:18: recipe for target 'poll' failed
make[1]: *** [poll] Error 1
make[1]: Leaving directory 'software/liburing/test'
Makefile:12: recipe for target 'all' failed
make: *** [all] Error 2

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

0 files changed, 0 insertions, 0 deletions