toolchain/gdb: use expat library to be able to parse target machine definitions

Fixes gdbserver debugging with at least mvebu, possibly others

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

SVN-Revision: 46298

toolchain/gdb/Makefile

@@ -17,11 +17,10 @@ HOST_BUILD_PARALLEL:=1
 
 include $(INCLUDE_DIR)/toolchain-build.mk
 
-define Host/Configure
-	(cd $(HOST_BUILD_DIR); \
-		gdb_cv_func_sigsetjmp=yes \
-		CFLAGS="-O2" \
-		$(HOST_BUILD_DIR)/configure \
+HOST_CONFIGURE_VARS += \
+	gdb_cv_func_sigsetjmp=yes
+
+HOST_CONFIGURE_ARGS = \
 	--prefix=$(TOOLCHAIN_DIR) \
 	--build=$(GNU_HOST_NAME) \
 	--host=$(GNU_HOST_NAME) \
@@ -31,8 +30,7 @@ define Host/Configure
 	--disable-tui --disable-gdbtk --without-x \
 	--without-included-gettext \
 	--enable-threads \
-	);
-endef
+	--with-expat
 
 define Host/Install
 	mkdir -p $(TOOLCHAIN_DIR)/bin