package/luajit: fix LUAJIT_XCFLAGS for host variant

As was just done for the target variant in commit 8d23bc990c2f
(package/luajit: fix LUAJIT_XCFLAGS), also fix the host variant
which uses the same flags.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/luajit/luajit.mk

@@ -68,7 +68,7 @@ LUAJIT_POST_INSTALL_TARGET_HOOKS += LUAJIT_INSTALL_SYMLINK
 define HOST_LUAJIT_BUILD_CMDS
 	$(HOST_MAKE_ENV) $(MAKE) PREFIX="$(HOST_DIR)" BUILDMODE=dynamic \
 		TARGET_LDFLAGS="$(HOST_LDFLAGS)" \
-		XCFLAGS=$(LUAJIT_XCFLAGS) \
+		XCFLAGS="$(LUAJIT_XCFLAGS)" \
 		-C $(@D) amalg
 endef