Fix manual page directory.

Index: Makefile
--- Makefile.orig
+++ Makefile
@@ -23,7 +23,7 @@ target_prefix = 
 program_suffix =
 prefix = /usr/local
 bindir = $(prefix)/bin
-man1dir = $(prefix)/share/man/man1
+man1dir = $(prefix)/man/man1
 
 src = dmd-script
 man = dmd-script.1
