Drop duplicate -optl's from GHC invocations
Previously the make build system would pass things like
-optl-optl-Wl,-x -optl-optl-Wl,noexecstack to GHC. This would
naturally result in mass confusion as GHC would pass -optl-Wl,-x to
GCC. GCC would in turn interpret this as -o ptl-Wl,-x, setting the
output pass of the invocation.
The problem that -optl was added to the command-line in two places in
the build system. Fix this.
Fixes Trac #17385.
(cherry picked from commit 2d12d59ec989d0f174f5f15e0a92cb1a9cc017e4)