[PATCH 0/3] MR6922: Improve clang configuration.

[eric pouech (＠epo)]

This MR improves configuration scheme when using clang as cross compiler:
- it fixes test for dwarf (-4) support (current test is failing as ldd emits
  a warning when generating the long section names for the dwarf section,
  that configure.ac treats as an error),
- it fixes --enable-build-id option with clang (clang linker uses -build-id
  option, while gcc uses --build-id /mind the extra '-'/)
- it adds support in winegcc for a generic build-id linker option.

(extracted from draft MR!6715)