We don't do unit testing when cross-compiling for now

Define the functions that adds the various check targets as empty when
cross-compiling. Avoids the needs for corresponding conditionals in
.mk files in modules.

Change-Id: Ia577e12204b516dc169a8500b4745aac4d7c24e2

solenv/gbuild/Module.mk

@@ -212,6 +212,19 @@ $(call gb_Module_get_clean_target,$(1)) : $$(gb_Module_CURRENTCLEANTARGET)
 
 endef
 
+ifeq ($(CROSS_COMPILING),YES)
+
+define gb_Module_add_check_target
+endef
+
+define gb_Module_add_slowcheck_target
+endef
+
+define gb_Module_add_subsequentcheck_target
+endef
+
+else
+
 define gb_Module_add_check_target
 $(call gb_Module__read_targetfile,$(1),$(2),check target)
 
@@ -236,6 +249,8 @@ $(call gb_Module_get_clean_target,$(1)) : $$(gb_Module_CURRENTCLEANTARGET)
 
 endef
 
+endif
+
 define gb_Module_add_moduledir
 include $(patsubst $(1):%,%,$(filter $(1):%,$(gb_Module_MODULELOCATIONS)))/$(2)/Module_$(2).mk
 $(call gb_Module_get_target,$(1)) : $$(firstword $$(gb_Module_TARGETSTACK))