I was wondering if there were any files in which I could set the -std=c99 flag, so that I would not have to set it for every compilation. I am using GCC 4.4 on Ubuntu.
Instead of calling /usr/bin/gcc, use /usr/bin/c99. This is the Single-Unix-approved way of invoking a C99 compiler. On an Ubuntu system, this points to a script which invokes gcc after having added the -std=c99 flag, which is precisely what you want.
How about alias gcc99= gcc -std=c99?
来源：https://stackoverflow.com/questions/2193634/setting-std-c99-flag-in-gcc