>>> conmon 2.1.8 Extracting
gzip -d -c /home/buildroot/autobuild/run/instance-3/dl/conmon/conmon-2.1.8.tar.gz | tar --strip-components=1 -C /home/buildroot/autobuild/run/instance-3/output-1/build/conmon-2.1.8   -xf -
>>> conmon 2.1.8 Patching

Applying 0001-src-seccomp_notify.c-fix-static-build.patch using patch: 
patching file src/seccomp_notify.c
>>> conmon 2.1.8 Configuring
printf '#!/bin/bash\necho "1"\n' > /home/buildroot/autobuild/run/instance-3/output-1/build/conmon-2.1.8/hack/seccomp-notify.sh
chmod +x /home/buildroot/autobuild/run/instance-3/output-1/build/conmon-2.1.8/hack/seccomp-notify.sh
>>> conmon 2.1.8 Building
GIT_DIR=. PATH="/home/buildroot/autobuild/run/instance-3/output-1/host/bin:/home/buildroot/autobuild/run/instance-3/output-1/host/sbin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin" /usr/bin/make -j4 CC="/home/buildroot/autobuild/run/instance-3/output-1/host/bin/arm-none-linux-gnueabi-gcc" CFLAGS="-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -O2 -g0 -D_FORTIFY_SOURCE=1" LDFLAGS="" -C /home/buildroot/autobuild/run/instance-3/output-1/build/conmon-2.1.8 bin/conmon
make[1]: Entering directory '/home/buildroot/autobuild/run/instance-3/output-1/build/conmon-2.1.8'
/home/buildroot/autobuild/run/instance-3/output-1/host/bin/arm-none-linux-gnueabi-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -O2 -g0 -D_FORTIFY_SOURCE=1 -I/home/buildroot/autobuild/run/instance-3/output-1/host/bin/../arm-buildroot-linux-gnueabi/sysroot/usr/include/glib-2.0 -I/home/buildroot/autobuild/run/instance-3/output-1/host/bin/../arm-buildroot-linux-gnueabi/sysroot/usr/lib/glib-2.0/include  -DVERSION=\"2.1.8\" -DGIT_COMMIT=\"\"  -o src/conmon.o -c src/conmon.c
/home/buildroot/autobuild/run/instance-3/output-1/host/bin/arm-none-linux-gnueabi-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -O2 -g0 -D_FORTIFY_SOURCE=1 -I/home/buildroot/autobuild/run/instance-3/output-1/host/bin/../arm-buildroot-linux-gnueabi/sysroot/usr/include/glib-2.0 -I/home/buildroot/autobuild/run/instance-3/output-1/host/bin/../arm-buildroot-linux-gnueabi/sysroot/usr/lib/glib-2.0/include  -DVERSION=\"2.1.8\" -DGIT_COMMIT=\"\"  -o src/cmsg.o -c src/cmsg.c
src/conmon.c:5:2: error: #error conmon.c requires C99 or later
 #error conmon.c requires C99 or later
  ^
/home/buildroot/autobuild/run/instance-3/output-1/host/bin/arm-none-linux-gnueabi-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -O2 -g0 -D_FORTIFY_SOURCE=1 -I/home/buildroot/autobuild/run/instance-3/output-1/host/bin/../arm-buildroot-linux-gnueabi/sysroot/usr/include/glib-2.0 -I/home/buildroot/autobuild/run/instance-3/output-1/host/bin/../arm-buildroot-linux-gnueabi/sysroot/usr/lib/glib-2.0/include  -DVERSION=\"2.1.8\" -DGIT_COMMIT=\"\"  -o src/ctr_logging.o -c src/ctr_logging.c
/home/buildroot/autobuild/run/instance-3/output-1/host/bin/arm-none-linux-gnueabi-gcc -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -O2 -g0 -D_FORTIFY_SOURCE=1 -I/home/buildroot/autobuild/run/instance-3/output-1/host/bin/../arm-buildroot-linux-gnueabi/sysroot/usr/include/glib-2.0 -I/home/buildroot/autobuild/run/instance-3/output-1/host/bin/../arm-buildroot-linux-gnueabi/sysroot/usr/lib/glib-2.0/include  -DVERSION=\"2.1.8\" -DGIT_COMMIT=\"\"  -o src/utils.o -c src/utils.c
src/cmsg.c:32:2: error: #error cmsg.c requires C99 or later
 #error cmsg.c requires C99 or later
  ^
Makefile:71: recipe for target 'src/cmsg.o' failed
make[1]: *** [src/cmsg.o] Error 1
make[1]: *** Waiting for unfinished jobs....
Makefile:71: recipe for target 'src/conmon.o' failed
make[1]: *** [src/conmon.o] Error 1
src/ctr_logging.c: In function 'configure_log_drivers':
src/ctr_logging.c:108:2: error: 'for' loop initial declarations are only allowed in C99 mode
  for (int driver = 0; log_drivers[driver]; ++driver) {
  ^
src/ctr_logging.c:108:2: note: use option -std=c99 or -std=gnu99 to compile your code
Makefile:71: recipe for target 'src/ctr_logging.o' failed
make[1]: *** [src/ctr_logging.o] Error 1
make[1]: Leaving directory '/home/buildroot/autobuild/run/instance-3/output-1/build/conmon-2.1.8'
package/pkg-generic.mk:280: recipe for target '/home/buildroot/autobuild/run/instance-3/output-1/build/conmon-2.1.8/.stamp_built' failed
make: *** [/home/buildroot/autobuild/run/instance-3/output-1/build/conmon-2.1.8/.stamp_built] Error 2
make: Leaving directory '/home/buildroot/autobuild/run/instance-3/buildroot'