Merge 9d1aebde66eb5c669e4b6928e17cdf6bd8fb6439 into e42f0e573221c5e0146c02fd5d71f32aa93c7221

preferably use the compiler(s) pre-installed on the system, then use those from `/toolchains/` if they do not exist, for the convenience of users who have not downloaded toolchains.

.gitignore

@@ -0,0 +1 @@
+/udp2raw*

README.md

@@ -81,7 +81,7 @@ Assume your UDP is blocked or being QOS-ed or just poorly supported. Assume your
 Now,an encrypted raw tunnel has been established between client and server through TCP port 4096. Connecting to UDP port 3333 at the client side is equivalent to connecting to port 7777 at the server side. No UDP traffic will be exposed.
 
 ### Note
-To run on Android, check [Android_Guide](/doc/android_guide.md)
+To run on Android, check [Android_Guide](https://github.com/wangyu-/udp2raw/wiki/Android-Guide)
 
 `-a` option automatically adds an iptables rule (or a few iptables rules) for you, udp2raw relies on this iptables rule to work stably. Be aware you dont forget `-a` (its a common mistake). If you dont want udp2raw to add iptables rule automatically, you can add it manually(take a look at `-g` option) and omit `-a`.
 

makefile

@@ -1,13 +1,13 @@
 cc_cross=/home/wangyu/Desktop/arm-2014.05/bin/arm-none-linux-gnueabi-g++
 cc_local=g++
-cc_mips24kc_be=/toolchains/lede-sdk-17.01.2-ar71xx-generic_gcc-5.4.0_musl-1.1.16.Linux-x86_64/staging_dir/toolchain-mips_24kc_gcc-5.4.0_musl-1.1.16/bin/mips-openwrt-linux-musl-g++
-cc_mips24kc_le=/toolchains/lede-sdk-17.01.2-ramips-mt7621_gcc-5.4.0_musl-1.1.16.Linux-x86_64/staging_dir/toolchain-mipsel_24kc_gcc-5.4.0_musl-1.1.16/bin/mipsel-openwrt-linux-musl-g++
-cc_arm= /toolchains/lede-sdk-17.01.2-bcm53xx_gcc-5.4.0_musl-1.1.16_eabi.Linux-x86_64/staging_dir/toolchain-arm_cortex-a9_gcc-5.4.0_musl-1.1.16_eabi/bin/arm-openwrt-linux-c++
+cc_mips24kc_be=$(shell which g++ || /toolchains/lede-sdk-17.01.2-ar71xx-generic_gcc-5.4.0_musl-1.1.16.Linux-x86_64/staging_dir/toolchain-mips_24kc_gcc-5.4.0_musl-1.1.16/bin/mips-openwrt-linux-musl-g++)
+cc_mips24kc_le=$(shell which g++ || /toolchains/lede-sdk-17.01.2-ramips-mt7621_gcc-5.4.0_musl-1.1.16.Linux-x86_64/staging_dir/toolchain-mipsel_24kc_gcc-5.4.0_musl-1.1.16/bin/mipsel-openwrt-linux-musl-g++)
+cc_arm= $(shell which c++ || /toolchains/lede-sdk-17.01.2-bcm53xx_gcc-5.4.0_musl-1.1.16_eabi.Linux-x86_64/staging_dir/toolchain-arm_cortex-a9_gcc-5.4.0_musl-1.1.16_eabi/bin/arm-openwrt-linux-c++)
 cc_mingw_cross=i686-w64-mingw32-g++-posix
 cc_mac_cross=o64-clang++ -stdlib=libc++
-cc_x86=/toolchains/lede-sdk-17.01.2-x86-generic_gcc-5.4.0_musl-1.1.16.Linux-x86_64/staging_dir/toolchain-i386_pentium4_gcc-5.4.0_musl-1.1.16/bin/i486-openwrt-linux-c++
-cc_amd64=/toolchains/lede-sdk-17.01.2-x86-64_gcc-5.4.0_musl-1.1.16.Linux-x86_64/staging_dir/toolchain-x86_64_gcc-5.4.0_musl-1.1.16/bin/x86_64-openwrt-linux-c++
-#cc_bcm2708=/home/wangyu/raspberry/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-g++ 
+cc_x86=$(shell which c++ || /toolchains/lede-sdk-17.01.2-x86-generic_gcc-5.4.0_musl-1.1.16.Linux-x86_64/staging_dir/toolchain-i386_pentium4_gcc-5.4.0_musl-1.1.16/bin/i486-openwrt-linux-c++)
+cc_amd64=$(shell which c++ || /toolchains/lede-sdk-17.01.2-x86-64_gcc-5.4.0_musl-1.1.16.Linux-x86_64/staging_dir/toolchain-x86_64_gcc-5.4.0_musl-1.1.16/bin/x86_64-openwrt-linux-c++)
+#cc_bcm2708=$(shell which g++ || /home/wangyu/raspberry/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-g++)
 
 
 FLAGS= -std=c++11   -Wall -Wextra -Wno-unused-variable -Wno-unused-parameter -Wno-missing-field-initializers ${OPT}