Change mapping definitions to be more similar to the libc prototypes, to
save on casting (particularly for x86-64, later). Handle alias maps via
a separate alias_mapping() function because here are two pointers instead
of pointer + offset.


git-svn-id: https://dosemu.svn.sourceforge.net/svnroot/dosemu/trunk@1592 7758b857-130e-0410-ab9c-d8735a528d18