fixed splitsymbols target to cd to correct directory. a=leaf

makefile.win

@@ -147,6 +147,8 @@ splitsymbols:
 !if defined(FIND)
 !if "$(SPLITSYM)" != ""
 	echo splitting symbols out of binaries
+	# componentreg leaves us in $(DIST)/bin
+	cd $(MOZ_SRC)\mozilla
 	$(FIND) $(DIST) -name "*.dll" -exec $(SPLITSYM) {} ;
 	$(FIND) $(DIST) -name "*.exe" -exec $(SPLITSYM) {} ;
 	$(FIND) $(DIST) -name "*.EXE" -exec $(SPLITSYM) {} ;