package/monkey: fix musl build

Fixes
http://autobuild.buildroot.net/results/f69/f690cb1efece8a47fccdf3e782bbde4d1b2cd6b3/
http://autobuild.buildroot.net/results/21b/21b6fa8b2586f318ff071085f2b204bd555b425b/
http://autobuild.buildroot.net/results/0bf/0bf7a83a4ccbbcb3ff181ac962e6fdd0099a19f1/

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/monkey/monkey.mk

@@ -30,7 +30,7 @@ MONKEY_CONF_OPTS += --uclib-mode --no-backtrace
 endif
 
 ifeq ($(BR2_TOOLCHAIN_USES_MUSL),y)
-MONKEY_CONF_OPTS += --musl-mode
+MONKEY_CONF_OPTS += --musl-mode --no-backtrace
 endif
 
 ifeq ($(BR2_PACKAGE_MONKEY_SHARED),y)