meson: fix subproject build regression

commit ae9ac2a1 from !165 introduced a regression when
fontconfig is built as a subproject. In that case we
would fail to correctly construct the path to the root
build dir where the meson-info subdirectory resides,
instead looking for it in the fontconfig subproject
subdir. This would result in
FAILED: subprojects/fontconfig/src/fcobjshash.gperf
errors in the script.

Instead use the @BUILD_ROOT@ substitution to get
to the build root which will work correctly in
either scenario.
1 file changed