gimp: Disable vector icons generation on mips/arm for musl targets
Fixes errors like
make[3]: *** [Makefile:2395: 24/document-print.svg] Segmentation fault (core dumped)
make[3]: *** [Makefile:2395: 24/gimp-center.svg] Segmentation fault (core dumped)
make[3]: *** [Makefile:2395: 24/media-optical.svg] Segmentation fault (core dumped)
make[3]: *** [Makefile:2395: 24/gimp-channel-gray.svg] Segmentation fault (core dumped)
make[3]: *** [Makefile:2395: 24/gimp-channel-blue.svg] Segmentation fault (core dumped)
make[3]: *** [Makefile:2395: 24/gtk-select-color.svg] Segmentation fault (core dumped)
make[3]: *** [Makefile:2395: 24/gimp-channel-alpha.svg] Segmentation fault (core dumped)
make[3]: *** [Makefile:2395: 24/media-floppy.svg] Segmentation fault (core dumped)
make[3]: *** [Makefile:2395: 24/gimp-business-card.svg] Segmentation fault (core dumped)
make[3]: *** [Makefile:2395: 24/gimp-channel.svg] Segmentation fault (core dumped)
make[3]: *** [Makefile:2395: 24/dialog-information.svg] Segmentation fault (core dumped)
Signed-off-by: Khem Raj <raj.khem@gmail.com>
Cc: Andreas Müller <schnitzeltony@gmail.com>