invoke.texi: Document Darwin linker options...

gcc
        *doc/invoke.texi: Document Darwin linker options, -bundle
        -bind_at_load, -all_load and -arch_errors_fatal

testsuite
        * gcc.dg/darwin-ld-1.c: New test.
        * gcc.dg/darwin-ld-2.c: New test.
        * gcc.dg/darwin-ld-3.c: New test.
        * gcc.dg/darwin-ld-4.c: New test.
        * gcc.dg/darwin-ld-5.c: New test.

From-SVN: r60081