C头文件调用路径：
export C_INCLUDE_PATH=/usr/local/include:$C_INCLUDE_PATH
#也可在gcc参数中指定调用路径
-I/usr/local/include C++头文件调用路径：
export CPLUS_INCLUDE_PATH=/usr/local/include:$CPLUS_INCLUDE_PATH动态库调用路径：
export LIBRARY_PATH=/usr/local/lib:$LIBRARY_PATH
#也可在gcc参数中指定调用路径
-L/usr/local/lib
#指定调用库的名字，如libcurl.so
-lcurlpkg-config路径：
export PKG_CONFIG_PATH=/usr/local/pkgconfig/程序运行时动态库调用路径：
export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH
#也可添加到全局动态库
echo '/usr/local/lib' > /etc/ld.so.conf.d/local.conf
ldconfig查看gcc默认查找头文件/动态库目录：
`gcc -print-prog-name=cc1` -v
gcc -print-search-dirs参考：http://www.cnblogs.com/vamei/archive/2013/04/04/2998850.html