package/civetweb: fix build without sync

If BR2_TOOLCHAIN_HAS_SYNC_4 is not set, define -DNO_ATOMICS=1 to
fallback on lock

Fixes:
 - http://autobuild.buildroot.org/results/7b3bc71d64aedf617dde35798099e16d7ae46713

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[Thomas: invert condition.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/civetweb/civetweb.mk

@@ -21,6 +21,10 @@ CIVETWEB_INSTALL_OPTS = \
 	HTMLDIR="$(TARGET_DIR)$(CIVETWEB_HTMLDIR)" \
 	SYSCONFDIR="$(TARGET_DIR)$(CIVETWEB_SYSCONFDIR)"
 
+ifeq ($(BR2_TOOLCHAIN_HAS_SYNC_4),)
+CIVETWEB_COPT += -DNO_ATOMICS=1
+endif
+
 ifeq ($(BR2_PACKAGE_CIVETWEB_WITH_LUA),y)
 CIVETWEB_CONF_OPTS += WITH_LUA=1
 CIVETWEB_LIBS += -ldl