netperf: fix compile with gcc >= 10

package/netperf/Makefile

@@ -18,6 +18,7 @@ include ${ADK_TOPDIR}/mk/package.mk
 
 $(eval $(call PKG_template,NETPERF,netperf,${PKG_VERSION}${PKG_RELEASE},${PKG_DEPENDS},${PKG_DESCR},${PKG_SECTION}))
 
+TARGET_CFLAGS+=		-fcommon
 # uClibc setpgrp does not take arguments
 CONFIGURE_ENV+=		ac_cv_func_setpgrp_void=yes