package/gdb: disable source-highlight
The dependency is not provided by Buildroot, and it can potentially be
found by gdb's build system from the host system, which results in the
following build errors:
../../gdb/source-cache.c:37:10: fatal error: srchilite/sourcehighlight.h: No such file or directory
37 | #include <srchilite/sourcehighlight.h>
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
make[4]: *** [Makefile:1645: source-cache.o] Error 1
make[4]: *** Waiting for unfinished jobs....
Signed-off-by: Bartosz Bilas <b.bilas@grinn-global.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>