(underscore.c): Rename rule to stamp-under, and touch stamp-under at the end.

(underscore.c): Rename rule to stamp-under, and touch stamp-under at
the end.  Add new rule for underscore.c that depends on stamp-under.

From-SVN: r10262

gcc/Makefile.in

@@ -1087,7 +1087,9 @@ collect2.o : collect2.c $(CONFIG_H) gstab.h obstack.h demangle.h
 
 cplus-dem.o: cplus-dem.c demangle.h
 
-underscore.c: $(GCC_PASSES)
+underscore.c: stamp-under ; @true
+
+stamp-under: $(GCC_PASSES)
 	echo "int xxy_us_dummy;" >tmp-dum.c
 	$(GCC_FOR_TARGET) -S tmp-dum.c
 	echo '/*WARNING: This file is automatically generated!*/' >tmp-under.c
@@ -1098,6 +1100,7 @@ underscore.c: $(GCC_PASSES)
 	fi
 	$(srcdir)/move-if-change tmp-under.c underscore.c
 	-rm -f tmp-dum.c tmp-dum.s
+	touch stamp-under
 
 # Objective C language specific files.