New/changed options

A number of command-line options for controlling warnings have changed, for compatibility with newer versions of the ARM tools.

• -fo (to enable "Old-style function") removed - it is now enabled by default for C90 and C99 modes.
• -Wd now disables "Old-style function" as well as "deprecated declaration".
• Warnings that are normally off can now be enabled with, -W+.
• -W+g enables warnings about unguarded or wrongly guarded header files.
• The old -Wg option (non-constant printf format) is now -Wh.
• -Wl controls "lower precision in wider context" separately from -Wn, which still controls both that and "implicit narrowing cast".
• -Ws (the "static initialiser in static data" warning) has been removed.
• -Wx disables "declared but not used" warnings.
• -W+u enables warnings about C++ keywords. This replaces the old -Wc option, which is now obsolescent.