tools: Fix support for Link-Time Optimization (LTO).
This makes some of the wine build tools handle LTO properly (when passed via CFLAGS/LDFLAGS in some way). Of course more work is needed for a successful build with LTO, but not that far fetched honestly (asm functions are the biggest issue, also because they can call "seemingly unused" C functions which have to be marked with the used
attribute). But that's for other MRs not related to wine tools.