Fix naming scheme for configure cache variables.
Fix naming scheme for configure cache variables.

In order to be cached, configure variables need to contain the
string '_cv_', and they should begin with a package-specific
prefix in order to avoid interfering with third-party macros.
Rename ld_dashr, ld_wl_rpath, ld_rpath to git_cv_ld_dashr etc.

Signed-off-by: Ralf Wildenhues <6ba98f67a915e494dbaafcb2b9f59e458e697276@gmx.de>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git