package/meson-tools: fix build with older gcc versions

package/meson-tools: fix build with older gcc versions

The meson-tools code uses C99 constructs without passing -std=c99,
which causes the build to fail with old gcc versions. Since there are
very few instances of C99 constructs, we simply patch them out.

Fixes:

 - http://autobuild.buildroot.net/results/602d474a12cf2400e4f38ffad903758d7fd9f2f5
 - http://autobuild.buildroot.net/results/65cfe582ce60fcff18afd008c3d469471ffb0e49

Signed-off-by: Dagg Stompler <daggs@gmx.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>