Makefile: SunOS 5.6 portability fix
Makefile: SunOS 5.6 portability fix

Although configure takes care of most of this, set some default values
for Solaris 2.6 (aka SunOS-5.6) to ensure git compiles even when
configure is not used to build it.

Signed-off-by: Gary V. Vaughan <f9023000f29773649f3850298becb9544b5fd6a9@thewrittenword.com>
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