[gcc-mips] fix compile error in 64bit system.

ERR MSG: real.h:82: error: size of array 'test_real_width' is negative

when gcc-mips compiling. it's first apply openwrt/toolchain/gcc.../patches.
it not apply package/gcc-mips/patches. so this patch is manuly apply this
patch.

Signed-off-by: Xiangfu Liu <xiangfu@sharism.cc>

gcc-mips/Makefile

@@ -45,6 +45,7 @@ endef
 
 define Build/Prepare
 	$(call Build/Prepare/Default)
+	($(CP) ./patches $(PKG_BUILD_DIR); cd $(PKG_BUILD_DIR); patch -Np1 < ./patches/001-cache-amnesia.patch;);
 	$(SED) 's,\(version_string.. = "[0-9\.]*\).*\(";\),\1 (OpenWrt-2.0)\2,' $(PKG_BUILD_DIR)/gcc/version.c
 	$(SED) 's,\(bug_report_url.. = "\).*\(";\),\1<URL:https://dev.openwrt.org/>\2,' $(PKG_BUILD_DIR)/gcc/version.c
 	(cd $(PKG_BUILD_DIR)/libstdc++-v3; autoconf;);

gcc-mips/patches/001-cache-amnesia.patch

@@ -0,0 +1,13 @@
+diff --git a/gcc/configure b/gcc/configure
+index f7d4161..7f11021 100755
+--- a/gcc/configure
++++ b/gcc/configure
+@@ -12972,7 +12972,7 @@ else
+ 	esac
+ 	saved_CFLAGS="${CFLAGS}"
+ 	CC="${CC_FOR_BUILD}" CFLAGS="${CFLAGS_FOR_BUILD}" \
+-	${realsrcdir}/configure \
++	CONFIG_SITE= ${realsrcdir}/configure --cache-file=./other.cache \
+ 		--enable-languages=${enable_languages-all} \
+ 		--target=$target_alias --host=$build_alias --build=$build_alias
+ 	CFLAGS="${saved_CFLAGS}"