DMD-like wrapper for GDC

 This package provides `gdmd`, an interface to the GNU D compiler (GDC), which
 recognizes flags normally used with the DMD D compiler and translates them to
 flags GDC can understand.
 This makes `gdmd` a drop-in replacement to the `dmd` compiler invocation.
 .
 The GNU D compiler compiles D sources using the gcc backend to generate
 highly optimized binaries.