Revert "mk: Allow parallel execution"

This reverts commit 71fbe92c2e.

Parallel make still does not work.

lisp/Makefile

@@ -1,3 +1,4 @@
+.NOTPARALLEL:	# always run this make serially
 .SUFFIXES:	# we don't need default suffix rules
 ifeq ($(MAKELEVEL), 0)
   $(error This make needs to be started as a sub-make from the toplevel directory.)
@@ -19,7 +20,7 @@ _ORGCM_ := dirall single native source slint1 slint2
 	install clean cleanauto cleanall cleanelc clean-install
 
 # do not clean here, done in toplevel make
-all compile compile-dirty::	 | autoloads
+all compile compile-dirty::	 autoloads
 ifeq ($(filter-out $(_ORGCM_),$(ORGCM)),)
 	$(MAKE) compile-$(ORGCM)
 else
@@ -27,11 +28,11 @@ else
 endif
 
 compile-dirall:	dirall
-compile-single: $(LISPC) | single
-compile-native: $(LISPN) | native
-compile-source:	| source dirall
-compile-slint1:	| dirall slint1
-compile-slint2:	| source dirall slint1
+compile-single: single $(LISPC)
+compile-native: native $(LISPN)
+compile-source:	source dirall
+compile-slint1:	dirall slint1
+compile-slint2:	source dirall slint1
 
 # internal
 dirall:

mk/targets.mk

@@ -1,4 +1,5 @@
 .EXPORT_ALL_VARIABLES:
+.NOTPARALLEL: .PHONY
 # Additional distribution files
 DISTFILES_extra=  Makefile etc
 
@@ -66,9 +67,9 @@ config config-test config-exe config-all config-version::
 	@echo ""
 
 oldorg:	compile info	# what the old makefile did when no target was specified
-uncompiled:	| cleanlisp autoloads	# for developing
+uncompiled:	cleanlisp autoloads	# for developing
 refcard:	card
-update update2::	| up0 clean autoloads all
+update update2::	up0 clean autoloads all
 
 single:	ORGCM=single
 single:	compile
@@ -127,7 +128,7 @@ $(INSTSUB):
 autoloads: lisp
 	$(MAKE) -C $< $@
 
-repro: | cleanall autoloads
+repro: cleanall autoloads
 	-@$(REPRO) &
 
 cleandirs: