fix(extra/language/c): should export LIBRARY_PATH as well

gcc looks for `LIBRARY_PATH` for library search path[^1] > LIBRARY_PATH > > The value of LIBRARY_PATH is a colon-separated list of directories, much like PATH. When configured as a native compiler, GCC tries the directories thus specified when searching for special linker files, if it cannot find them using GCC_EXEC_PREFIX. Linking using GCC also uses these directories when searching for ordinary libraries for the -l option (but directories specified with -L come first). > [^1]: https://gcc.gnu.org/onlinedocs/gcc-12.5.0/gcc/Environment-Variables.html#:~:text=LIBRARY_PATH