Update prereq-build.mk

[ZeroForce423]

解决feed update时，检测不出当前 gcc/g++ v11 最新版本的报错 (简单的把10改到11就能用，但不懂代码不明白怎么改才是正确的语法)：
Build dependency: Please install the GNU C Compiler (gcc) 4.8 or later
Build dependency: Please install the GNU C++ Compiler (g++) 4.8 or later

$ gcc --version
gcc (Ubuntu 11.2.0-7ubuntu2) 11.2.0

[lihonfu]

Patch failed! Please fix /home/q/openwrt/target/linux/generic/backport-4.19/210-arm64-sve-Disentangle-uapi-asm-ptrace.h-from-uapi-as.patch!
make[3]: *** [Makefile:113: /home/q/openwrt/build_dir/toolchain-arm_cortex-a9+vfpv3_gcc-7.5.0_musl_eabi/linux-4.19/.prepared] Error 1
make[3]: Leaving directory '/home/q/openwrt/toolchain/kernel-headers'
time: toolchain/kernel-headers/compile#2.90#12.77#11.03
make[2]: *** [toolchain/Makefile:100: toolchain/kernel-headers/compile] Error 2
make[2]: Leaving directory '/home/q/openwrt'
make[1]: *** [toolchain/Makefile:96: /home/q/openwrt/staging_dir/toolchain-arm_cortex-a9+vfpv3_gcc-7.5.0_musl_eabi/stamp/.toolchain_compile] Error 2
make[1]: Leaving directory '/home/q/openwrt'
make: *** [/home/q/openwrt/include/toplevel.mk:227：world] 错误 2
怎么搞,怎么搞?问几天了..