Change *mandir targets to use new *_MAN_DIR variables set by xorg-macros.m4

    update to fix bug #5167 (Linux prefers *.1x man pages in man1 subdir)

man/Makefile.am

@@ -25,7 +25,7 @@
 # from the copyright holders.
 # 
 
-drivermandir = $(mandir)/man$(DRIVER_MAN_SUFFIX)
+drivermandir = $(DRIVER_MAN_DIR)
 
 driverman_SOURCES = @DRIVER_NAME@.man