makefile: updated some make scripts to use when calling subdir makefiles

Makefile

@@ -1,19 +1,19 @@
 all:
-	cd Tools/unix ; make
-	cd Source ; make
-	cd Source/Images ; make
+	$(MAKE) --directory Tools/unix
+	$(MAKE) --directory Source
+	$(MAKE) --directory Source/Images
 
 clean:
-	cd Tools/unix ; make clean
-	cd Source ; make clean
-	cd Binary ; make clean
+	$(MAKE) --directory Tools/unix clean
+	$(MAKE) --directory Source clean
+	$(MAKE) --directory Binary clean
 
 clobber:
-	cd Tools/unix ; make clobber
-	cd Source ; make clobber
-	cd Binary ; make clobber
+	$(MAKE) --directory Tools/unix clobber
+	$(MAKE) --directory Source  clobber
+	$(MAKE) --directory Binary clobber
 	rm -f typescript
 
 diff:
-	cd Source ; make diff
+	$(MAKE) --directory diff
 

Tools/Makefile.inc

@@ -94,6 +94,8 @@ ifeq ($(UNAME), Linux)
 	$(BSTC) -e -l $<
 endif
 
+.ONESHELL:
+
 #
 # darwin bstc won't run, since mac os does not do 32 bit binaries any more
 # openspin ought to work
@@ -108,7 +110,7 @@ endif
 #
 all:: $(OBJECTS)
 	@for dir in $(SUBDIRS) ; do \
-		( echo "building in `pwd`/$$dir" ; cd "$$dir" ; make all ) ; \
+		( echo "building in `pwd`/$$dir" ; $(MAKE) --directory "$$dir" all ) ; \
 	done
 	@if [ "$(DEST)" ] ; then for file in $(OBJECTS) ; do \
 		mkdir -p $(DEST) ; \