x11-terms/tilix-1.9.3-r1 fails to compile with gdc 9.3

[KingDuckZ]

As per the title, I set the use flag gdc-9_3_0 and I get the following build error:

gdmd: unrecognized switch '-shared-libphobos'

[mleise]

I got unrecognized switch '-O3' and since LLVM 8 is gone and took older LDC2 versions with it, I removed the DC=$DMD part that made it invoke the dmd wrapper script and fixes this issue. The result is that it now fails to compile due to shared/constness issues in object.d. Basically on an up-to-date Gentoo, only dmd works.