GHC Used to only allow for one include mode, namely -I.
The problem with -I includes is that it supercedes all other
includes, including the system include paths.
This is not a problem for paths requested by the user, but it is a
problem for the ones we implicitly derive and add.
In particular we add the source directory of the input file to the
include path. This is problematic because it causes any file with the
name of a system include, to inadvertently loop as the wrong file gets
Since this is an implicitly include, and as far as I can tell, only done
so local includes are found (as the sources given to GCC reside in a temp
folder) then switch from -I to -iquote.