This patch introduces two "generic" pseudo targets to simplify testing
the changes to builtins library on a developer machine.
- ignore any target-specific subdirectories
- use the specified size of long double (this may simplify testing of QUAD_PRECISION libcall variants when working on a generic implementation on an X86 host)
- are intended *for testing only*
- may produce false positives (at least when non-default size of long double is selected)