Localization fixes.
* c-decl.c (parmlist_tags_warning, start_struct,
check_for_loop_decls): Separate messages for struct, union and
enum cases to allow for languages in which they have different
genders.
* c-format.c (scanf_flag_specs): Separate short and long name of
the assignment suppression feature.
(check_format_types): Localize "pointer" and "different types"
strings.
* c-lex.c (lex_number): Localize "an unsigned long int" and
related strings.
(lex_string) [MULTIBYTE_CHARS]: Use initial lowercase letter on
warning message.
* c-typeck.c (build_unary_up): Separate messages for increment and
decrement cases to allow for languages in which they use different
articles. Localize the strings "increment" and "decrement" in one
case.