config.mak.in: Pass on LDFLAGS from configure

The configure script allows you to specify flags to pass to the linker
step in the LDFLAGS environment variable but this was being ignored in
the Makefile. Now a make variable gets set to the value passed down
from the configure script.

Signed-off-by: Neil Roberts <bpeeluk@yahoo.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config.mak.in

@@ -3,6 +3,7 @@
 
 CC = @CC@
 CFLAGS = @CFLAGS@
+LDFLAGS = @LDFLAGS@
 AR = @AR@
 TAR = @TAR@
 #INSTALL = @INSTALL@		# needs install-sh or install.sh in sources