x64 command line build cleanup

x64 command line build cleanup

64-bit linker had a number of warnings that the 32-bit linker did not.
It turned out to be because the 64-bit compiler is more picky about
declaring DLL exports 2-different ways, even if they are essentially
the same. The 32-bit linkder didn't complain. It is described here:
http://support.microsoft.com/kb/835326

The warnings that this suppresses are:

nhdefkey.c
Linking hdefkey.dll
Microsoft (R) Incremental Linker Version 10.00.40219.01
Copyright (C) Microsoft Corporation.  All rights reserved.

nhdefkey.o : warning LNK4197: export 'ProcessKeystroke' specified multiple times; using first specification
nhdefkey.o : warning LNK4197: export 'NHkbhit' specified multiple times; using first specification
nhdefkey.o : warning LNK4197: export 'CheckInput' specified multiple times; using first specification
nhdefkey.o : warning LNK4197: export 'SourceWhere' specified multiple times; using first specification
nhdefkey.o : warning LNK4197: export 'SourceAuthor' specified multiple times; using first specification
nhdefkey.o : warning LNK4197: export 'KeyHandlerName' specified multiple times; using first specification
   Creating library o\nhdefkey.lib and object o\nhdefkey.exp

nh340key.c
Linking h340key.dll
nh340key.o : warning LNK4197: export 'ProcessKeystroke' specified multiple times; using first specification
nh340key.o : warning LNK4197: export 'NHkbhit' specified multiple times; using first specification
nh340key.o : warning LNK4197: export 'CheckInput' specified multiple times; using first specification
nh340key.o : warning LNK4197: export 'SourceWhere' specified multiple times; using first specification
nh340key.o : warning LNK4197: export 'SourceAuthor' specified multiple times; using first specification
nh340key.o : warning LNK4197: export 'KeyHandlerName' specified multiple times; using first specification
   Creating library o\nh340key.lib and object o\nh340key.exp

nhraykey.c
Linking hraykey.dll
nhraykey.o : warning LNK4197: export 'ProcessKeystroke' specified multiple times; using first specification
nhraykey.o : warning LNK4197: export 'CheckInput' specified multiple times; using first specification
nhraykey.o : warning LNK4197: export 'NHkbhit' specified multiple times; using first specification
nhraykey.o : warning LNK4197: export 'SourceWhere' specified multiple times; using first specification
nhraykey.o : warning LNK4197: export 'SourceAuthor' specified multiple times; using first specification
nhraykey.o : warning LNK4197: export 'KeyHandlerName' specified multiple times; using first specification
   Creating library o\nhraykey.lib and object o\nhraykey.exp