Fixed man page path

According to the FHS, /usr/local/share/man is the correct man page path
in this projects's case. Set this to default in config.mk.

config.mk

@@ -5,7 +5,7 @@ VERSION = 0
 
 #paths
 PREFIX = /usr/local
-MANPREFIX = ${PREFIX}/man
+MANPREFIX = ${PREFIX}/share/man
 
 X11INC = /usr/X11R6/include
 X11LIB = /usr/X11R6/lib