Index: /trunk/source/lisp-kernel/darwinx8632/Makefile
===================================================================
--- /trunk/source/lisp-kernel/darwinx8632/Makefile	(revision 13046)
+++ /trunk/source/lisp-kernel/darwinx8632/Makefile	(revision 13047)
@@ -70,5 +70,5 @@
 OSLIBS = $(OSEARLYLIBS) $(OSMIDDLELIBS) $(OSLATELIBS)
 
-../../dx86cl:	 $(KSPOBJ) $(KERNELOBJ) $(DEBUGOBJ) Makefile
+../../dx86cl:	 tiger-sdk-check $(KSPOBJ) $(KERNELOBJ) $(DEBUGOBJ) Makefile
 	$(LD)  $(LDFLAGS) $(KSPOBJ) $(KERNELOBJ) $(DEBUGOBJ)   $(OSLIBS)
 
@@ -95,2 +95,8 @@
 	strip -s retain ../../dx86cl
 
+.PHONY: tiger-sdk-check
+tiger-sdk-check:
+	@test -d /Developer/SDKs/MacOSX10.4u.sdk || \
+		 (echo "*** Install Xcode 10.4 support"; exit 1)
+
+
Index: /trunk/source/lisp-kernel/darwinx8664/Makefile
===================================================================
--- /trunk/source/lisp-kernel/darwinx8664/Makefile	(revision 13046)
+++ /trunk/source/lisp-kernel/darwinx8664/Makefile	(revision 13047)
@@ -93,5 +93,5 @@
 OSLIBS = $(OSEARLYLIBS) $(OSMIDDLELIBS) $(OSLATELIBS)
 
-../../dx86cl64:	 $(KSPOBJ) $(KERNELOBJ) $(DEBUGOBJ) Makefile
+../../dx86cl64:	 tiger-sdk-check $(KSPOBJ) $(KERNELOBJ) $(DEBUGOBJ) Makefile
 	$(LD) $(LDFLAGS) $(KSPOBJ) $(KERNELOBJ)  $(DEBUGOBJ) $(OSLIBS)
 
@@ -115,2 +115,8 @@
 strip:	../../dx86cl64
 	strip -s retain ../../dx86cl64
+
+.PHONY: tiger-sdk-check
+tiger-sdk-check:
+	@test -d /Developer/SDKs/MacOSX10.4u.sdk || \
+		(echo "*** Install Xcode 10.4 support"; exit 1)
+