Compiler warning triggered when compiling without -Wmaybe-uninitialized

[eyalroz]

This preprocessor directive:

#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"

on line 939 of src/printf/printf.c will fail if the option is unknown. It's known if you build with the provided CMakeLists.txt, but otherwise - it might not be, and we dopn't want:

src/printf/printf.c:659:32: warning: unknown warning group '-Wmaybe-uninitialized', ignored [-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
                               ^
src/printf/printf.c:939:32: warning: unknown warning group '-Wmaybe-uninitialized', ignored [-Wunknown-warning-option]
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"

littering our output.