utils.c: fix static build

Static build fails since version 1.17.1 and 1e488d43 on:

FAILED: tools/ges-launch-1.0
/srv/storage/autobuild/run/instance-2/output-1/host/bin/arm-linux-gcc  -o tools/ges-launch-1.0 tools/ges-launch-1.0.p/ges-validate.c.o tools/ges-launch-1.0.p/ges-launch.c.o tools/ges-launch-1.0.p/ges-launcher.c.o tools/ges-launch-1.0.p/utils.c.o -Wl,--as-needed -Wl,--no-undefined -Wl,-O1 -Wl,-Bsymbolic-functions -static -Wl,--start-group ges/libges-1.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libgstreamer-1.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libgobject-2.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libglib-2.0.a -pthread /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libpcre.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libffi.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libgmodule-2.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libgstbase-1.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libgstvideo-1.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libgstpbutils-1.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libgstaudio-1.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libz.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libgsttag-1.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libgstcontroller-1.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libgio-2.0.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libmount.a /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libblkid.a -lm -Wl,--end-group
/srv/storage/autobuild/run/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-uclibcgnueabi/8.3.0/../../../../arm-buildroot-linux-uclibcgnueabi/bin/ld: /srv/storage/autobuild/run/instance-2/output-1/host/arm-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libc.a(err.os): in function `warn':
err.c:(.text+0x1d8): multiple definition of `warn'; tools/ges-launch-1.0.p/utils.c.o:utils.c:(.text+0x9bc): first defined here

So rename warn function to gst_warn

Fixes:

• http://autobuild.buildroot.org/results/2a528a1185644f5b23d26eb3f2b342e99aa1e493

Signed-off-by: Fabrice Fontaine fontaine.fabrice@gmail.com