build: NonStop ships with an older zlib

Notably, it lacks uncompress2(); use the fallback we ship in our
tree instead.

Signed-off-by: Randall S. Becker <rsbecker@nexbridge.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: rsbeckerca

config.mak.uname

@@ -576,6 +576,7 @@ ifeq ($(uname_S),NONSTOP_KERNEL)
 	NO_SETENV = YesPlease
 	NO_UNSETENV = YesPlease
 	NO_MKDTEMP = YesPlease
+	NO_UNCOMPRESS2 = YesPlease
 	# Currently libiconv-1.9.1.
 	OLD_ICONV = UnfortunatelyYes
 	NO_REGEX = NeedsStartEnd