[AD] msvc compiler options

[aj <aj@xxxxxxxxxx>]

could allegro benefit from the /GL  compiler option.

Whole Program Optimization,  which can inline accross module boundaries.

reference:   a list of all the MSVC compiler options
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccore/html/vcrefcompileroptionslistedalphabetically.asp


aj.