configure: auto detect dynamic library path switches
Most systems (e.g. Linux gcc) use "-Wl,-rpath," to pass to the linker the
runtime dynamic library paths. Some other systems (e.g. Sun, some BSD) use
"-R" etc. This patch adds tests in configure for the three most common
switches (to my best knowledge) which should cover all current platforms
where Git is used.
Signed-Off-By: Giovanni Funchal <gafunchal@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>