Cabal tries to use GHC to configure LD

**Describe the bug**
Cabal uses a peculiar c program to check if LD supports and should use -x. To do this, it shells out to GHC to compiler the C file. This however requires that GHC will not bail out, yet cabal does not pass --package-db flags to this GHC invocation, and as such we can run into situations where GHC bails out, especially during GHC bootstrap phases where not all boot packages are available.

**To Reproduce**
Steps to reproduce the behavior:
Kill GHC's --package-db (including it's shipped one).

then try to build _anything_.

```
$ cabal build ...
```

**Expected behavior**
cabal doesn't bail out trying to configure ld, but ghc fails during the configuration step.

=> Cabal should use GCC not GHC to test C features.