Use an explicit $(SHELL) for shell scripts so that pymake is happy, no bug, r=ted

Makefile.in

@@ -197,7 +197,7 @@ endif # MOZ_CRASHREPORTER
 
 uploadsymbols:
 ifdef MOZ_CRASHREPORTER
-	$(topsrcdir)/toolkit/crashreporter/tools/upload_symbols.sh "$(DIST)/$(SYMBOL_ARCHIVE_BASENAME).zip"
+	$(SHELL) $(topsrcdir)/toolkit/crashreporter/tools/upload_symbols.sh "$(DIST)/$(SYMBOL_ARCHIVE_BASENAME).zip"
 endif
 
 ifeq ($(OS_ARCH),WINNT)