-Wincompatible-pointer-types
#
# In GCC 4.4.7, the compiler gripes about shadowed global
# declarations when a local variable uses the name of a
# function that's in a system header file.  For some reason,
# later versions of GCC (e.g., 5.2.0) don't complain about
# the shadowed globals.  Maybe later versions are less fussy?
# Anyway, the shadowing seems to be harmless, and GCC 4.4.7
# is not a supported compiler, so let us promote shadowed globals
# warnings to errors only for GCC 5 and later.
#
-Wshadow