use an if block on the whole configure command

SVN-Revision: 4717

openwrt/include/package.mk

@@ -263,7 +263,7 @@ endef
 
 define Build/Configure/Default
 	@(cd $(PKG_BUILD_DIR)/$(3); \
-	[ \! -x configure ] || \
+	if [ -x configure ]; then \
 		$(TARGET_CONFIGURE_OPTS) \
 		CFLAGS="$(TARGET_CFLAGS)" \
 		CPPFLAGS="-I$(STAGING_DIR)/usr/include -I$(STAGING_DIR)/include" \
@@ -287,6 +287,7 @@ define Build/Configure/Default
 		--infodir=/usr/info \
 		$(DISABLE_NLS) \
 		$(1); \
+	fi; \
 	)
 endef