Index: /trunk/magic/Makefile
===================================================================
--- /trunk/magic/Makefile	(revision 28065)
+++ /trunk/magic/Makefile	(revision 28066)
@@ -3,4 +3,6 @@
 QTDIR = qt-everywhere-opensource-src-4.6.1
 QTSRC = ~/magic_tarballs/qt-everywhere-opensource-src-4.6.1.tar.gz
+QTDEP := $(shell test -f $(QTSRC) && echo $(QTSRC))
+
 PSCFG = ../psconfig/psconfig.csh
 PSPREFIX := $(shell csh $(PSCFG) $(PSVERSION) --prefix)
@@ -44,5 +46,6 @@
 	-no-scripttools 
 
-$(QTDIR)/lib/libQtCore.so: $(QTSRC)
+# the target (QTDEP) is blank unless QTSRC exists
+$(QTDIR)/lib/libQtCore.so: $(QTDEP)
 	echo $(PSCFG)
 	echo $(PSPREFIX)