ar: Add --thin for creating thin archives

In many ar implementations (FreeBSD, elfutils, etc), -T has the X/Open
System Interface specified semantics. Therefore -T for thin archives is
not recommended for portability. -T is deprecated without diagnostics.

    PR binutils/28759
    * ar.c (long_options): Add --thin.
    (usage) Add --thin. Deprecate -T without diagnostics.
    * doc/binutils.texi: Add doc.
    * NEWS: Mention --thin.
    * binutils/testsuite/binutils-all/ar.exp: Add tests.
5 files changed