always compile breakpad with O2

Change-Id: I4cda93fee47244cf3eb7b13bb6cb2a3eab007cf0
diff --git a/external/breakpad/ExternalProject_breakpad.mk b/external/breakpad/ExternalProject_breakpad.mk
index 70df68e..10fa6ce 100644
--- a/external/breakpad/ExternalProject_breakpad.mk
+++ b/external/breakpad/ExternalProject_breakpad.mk
@@ -20,7 +20,7 @@ else # !ifeq($(COM),MSC)

$(call gb_ExternalProject_get_state_target,breakpad,build) :
	$(call gb_ExternalProject_run,build,\
		./configure \
		CXX_FLAGS="-O2" ./configure \
		&& $(MAKE) \
	)