iPXE - Open Source Boot Firmware

[build] Use positive-form tests when checking for supported warnings
authorMichael Brown <mcb30@ipxe.org>
Sun, 8 Jul 2018 17:12:43 +0000 (18:12 +0100)
committerMichael Brown <mcb30@ipxe.org>
Sun, 8 Jul 2018 17:17:18 +0000 (18:17 +0100)
commit1c47eb186e7e38bde2a1db528cc3557b1b300386
tree4e0a7ea00637813e37dd3916abc31ffcfdcaf439
parent40956545e25103fcc4c22e496e4d1d842e2aac53
[build] Use positive-form tests when checking for supported warnings

Some versions of gcc seem to silently accept an attempt to disable an
unrecognised warning (e.g. via -Wno-stringop-truncation) but will then
report the unrecognised warning if any other error occurs during the
build, resulting in a potentially misleading error message.

Avoid this potential confusion by using the positive-form tests in
order to determine the workaround CFLAGS.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
src/Makefile.housekeeping