Fix 'make all' to build all the way through stage2. Closes #3978

Makefile.in

@@ -351,13 +351,13 @@ TSREQ$(1)_T_$(2)_H_$(3) = \
 	$$(TLIB$(1)_T_$(2)_H_$(3))/$$(CFG_RUNTIME) \
 	$$(TLIB$(1)_T_$(2)_H_$(3))/libmorestack.a
 
-# Prerequisites for a working stageN compiler and libraries
+# Prerequisites for a working stageN compiler and libraries, for a specific target
 SREQ$(1)_T_$(2)_H_$(3) = \
 	$$(TSREQ$(1)_T_$(2)_H_$(3)) \
 	$$(TLIB$(1)_T_$(2)_H_$(3))/$$(CFG_CORELIB) \
 	$$(TLIB$(1)_T_$(2)_H_$(3))/$$(CFG_STDLIB)
 
-# Prerequisites for a working stageN compiler and libraries
+# Prerequisites for a working stageN compiler and libraries, for a specific target
 CSREQ$(1)_T_$(2)_H_$(3) = \
 	$$(TSREQ$(1)_T_$(2)_H_$(3)) \
 	$$(HBIN$(1)_H_$(3))/fuzzer$$(X) \
@@ -472,11 +472,22 @@ CFG_INFO := $(info cfg: *** compiler is in snapshot transition ***)
 CFG_INFO := $(info cfg: *** stage2 and later will not be built ***)
 CFG_INFO := $(info cfg:)
 
+#XXX This is surely busted
 all: $(SREQ1$(CFG_HOST_TRIPLE)) $(GENERATED) docs
 
 else
 
-all: $(CSREQ3$(CFG_HOST_TRIPLE)) $(GENERATED) docs
+define ALL_TARGET_N
+all-target-$(1)-host-$(2): $$(CSREQ2_T_$(1)_H_$(2))
+endef
+
+$(foreach target,$(CFG_TARGET_TRIPLES), \
+ $(eval $(call ALL_TARGET_N,$(target),$(CFG_HOST_TRIPLE))))
+
+ALL_TARGET_RULES = $(foreach target,$(CFG_TARGET_TRIPLES), \
+ all-target-$(target)-host-$(CFG_HOST_TRIPLE))
+
+all: $(ALL_TARGET_RULES) $(GENERATED) docs
 
 endif