configure: avoid testing for negative compiler options

gcc seems to always accept unsupported negative compiler warning options:

echo "int i;" | gcc -c -xc -Wno-bob - # no error
echo "int i;" | gcc -c -xc -Walice -  # unsupported compiler option

Inverting the options fixes the tests.

V2: fix options in meson build

Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Signed-off-by: Marc Dietrich <marvin24@gmx.de>
2 files changed