missing functions in x86-64 compiled .lib files

[smokingplaya]

On the master (x86) branch, all tier0 functions, including SpewOutputFunc and GetSpewOutputFunc from tier0/dbg.h are exported properly.

On x86-64 branch, these functions are missing in the compiled .lib/.def so the linker blows up with undefined references.

Issue #48 is probably related to this.