Drop runtime linker/compiler configuration in favour of configure-time configuration
As parts of the efforts for #19877 (closed), we're removing the runtime linker/compiler checks in favour of configuring the toolchain at configure time
We used to choose flags to pass to the toolchain at runtime based on the platform running GHC, and we propose to drop all of those runtime linker/compiler checks
Ultimately, this represents a change in policy: We no longer adapt at runtime to the toolchain being used, but rather make final decisions about the toolchain used at /configure time/ (we have deleted Note [Run-time linker info] altogether!).
This works towards the goal of having all toolchain configuration logic living in the same place, which facilities the work towards a runtime-retargetable GHC (see #19877 (closed)).
This ticket can be closed when we remove the runtime linker/compiler checks and move them into configure.
Fix in !10723 (closed)