man: Makefile.am: use platform appropriate sed and enable silent build

Author: merge

man/Makefile.am

@@ -35,8 +35,6 @@ EXTRA_DIST = @DRIVER_NAME@.man
 
 CLEANFILES = $(driverman_DATA)
 
-SED = sed
-
 # Strings to replace in man pages
 XORGRELSTRING = @PACKAGE_STRING@
   XORGMANNAME = X Version 11
@@ -56,4 +54,4 @@ MAN_SUBSTS = \
 SUFFIXES = .$(DRIVER_MAN_SUFFIX) .man
 
 .man.$(DRIVER_MAN_SUFFIX):
-	sed $(MAN_SUBSTS) < $< > $@
+	$(AM_V_GEN)$(SED) $(MAN_SUBSTS) < $< > $@