DDMD: Fix duplicate definition linker errors in gdc

[ibuclaw]

As per discussion, dmd does some fancy section trick to evade this. But it just won't fly in gdc.

@klickverbot - would this bug you?

[yebblies]

You should probably make up a new version for these and set it from the command line, eg version=OverrideAllocationFunctions. Host compiler conditions really don't belong in here.

[MartinNowak]

It also doesn't work with LDC b/c only dmd creates multilibs.

[MartinNowak]

We should make a GC proxy to override the allocations. Simply disabling them for GDC/LDC is a major slowdown.

[yebblies]

We should make a GC proxy to override the allocations. Simply disabling them for GDC/LDC is a major slowdown.

That's outside my expertise. How complicated is it?

[dnadlinger]

We should make a GC proxy to override the allocations. Simply disabling them for GDC/LDC is a major slowdown.

In the preliminary tests we did after DConf, it did not seem to make much of a difference. But yeah, we should look into such optimizations after the merge.

[MartinNowak]

Let's deactivate the stuff for now.