gbuild: CppunitTest: don't hang with DEBUGCPPUNIT=TRUE ...

... if the process exits before the "bt" command, because then gdb will
print an error that there is no stack and stop the script before "quit".

Change-Id: I0f3a1381e17dda7e8a7d958e0cbc96676bbc23ce

solenv/gbuild/CppunitTest.mk

@@ -20,7 +20,7 @@
 # CppunitTest class
 
 ifeq ($(strip $(DEBUGCPPUNIT)),TRUE)
-gb_CppunitTest_GDBTRACE := gdb -nx -ex "add-auto-load-safe-path $(INSTDIR)" --command=$(SRCDIR)/solenv/bin/gdbtrycatchtrace-stdout -return-child-result --args
+gb_CppunitTest_GDBTRACE := gdb -nx -ex "add-auto-load-safe-path $(INSTDIR)" --batch --command=$(SRCDIR)/solenv/bin/gdbtrycatchtrace-stdout -return-child-result --args
 else ifneq ($(strip $(CPPUNITTRACE)),)
 gb_CppunitTest_GDBTRACE := $(CPPUNITTRACE)
 gb_CppunitTest__interactive := $(true)