crt: Document all common CRT aliases

Add a new helper macro ADD_UNDERSCORE_DATA for defining alias for
underscored DATA symbol.

Move symbol aliases into categories and document from which oldnames.lib
version they comes from or what is the reason for defining them (C99, POSIX
or GNU compatibility).

Document all symbols from the latest oldnames.lib library. Aliases were not
modified since Visual C++ 4.0. Missing symbol aliases were added as a
comment (and they can be enabled later by additional changes).

Signed-off-by: Martin Storsjö <martin@martin.st>
1 file changed