A (work in progress) compilation of useful GCC configuration, focused on C. -W warnings. -Wall is a must. -Werror to treat warnings as errors. -l instructs the linker it has some work to do (i.e. link a library please). -lm is shorthand for -libm and in turn -libm.a is a static library is selected. -L hint to the linker where to locate libraries. -L/opt/gdbm-1.10/src in combination with -lgdbm tells the linker exactly where to find the gdbm libraries.