gbuild: improve error messages about missing registrations

Change-Id: Ib3c5d8f3921801f143447d8e01463905d80ac319

solenv/gbuild/Executable.mk

@@ -59,7 +59,7 @@ define gb_Executable_Executable
 $(call gb_Postprocess_register_target,AllExecutables,Executable,$(1))
 ifeq (,$$(findstring $(1),$$(gb_Executable_KNOWN)))
 $$(eval $$(call gb_Output_info,Currently known executables: $(sort $(gb_Executable_KNOWN)),ALL))
-$$(eval $$(call gb_Output_error,Executable $(1) must be registered in Repository.mk))
+$$(eval $$(call gb_Output_error,Executable $(1) must be registered in Repository.mk or RepositoryExternal.mk))
 endif
 $(call gb_Executable__Executable_impl,$(1),$(call gb_Executable_get_linktarget,$(1)))
 

solenv/gbuild/ExternalProject.mk

@@ -178,7 +178,7 @@ endef
 define gb_ExternalProject_use_libraries
 ifneq (,$$(filter-out $(gb_Library_KNOWNLIBS),$(2)))
 $$(eval $$(call gb_Output_info,currently known libraries are: $(sort $(gb_Library_KNOWNLIBS)),ALL))
-$$(eval $$(call gb_Output_error,Cannot link against library/libraries $$(filter-out $(gb_Library_KNOWNLIBS),$(2)). Libraries must be registered in Repository.mk))
+$$(eval $$(call gb_Output_error,Cannot link against library/libraries $$(filter-out $(gb_Library_KNOWNLIBS),$(2)). Libraries must be registered in Repository.mk or RepositoryExternal.mk))
 endif
 ifneq (,$$(filter $$(gb_MERGEDLIBS),$(2)))
 $$(eval $$(call gb_Output_error,Cannot link against library/libraries $$(filter $$(gb_MERGEDLIBS),$(2)) because they are merged.))

solenv/gbuild/Jar.mk

@@ -95,7 +95,7 @@ endef
 define gb_Jar_Jar
 ifeq (,$$(findstring $(1),$$(gb_Jar_KNOWN)))
 $$(eval $$(call gb_Output_info,Currently known jars are: $(sort $(gb_Jar_KNOWN)),ALL))
-$$(eval $$(call gb_Output_error,Jar $(1) must be registered in Repository.mk))
+$$(eval $$(call gb_Output_error,Jar $(1) must be registered in Repository.mk or RepositoryExternal.mk))
 endif
 $(call gb_Jar_get_target,$(1)) : MANIFEST :=
 $(call gb_Jar_get_target,$(1)) : JARCLASSPATH :=

solenv/gbuild/JavaClassSet.mk

@@ -108,7 +108,7 @@ endef
 define gb_JavaClassSet_use_jar
 ifneq (,$$(filter-out $(gb_Jar_KNOWN),$(2)))
 $$(eval $$(call gb_Output_info,currently known jars are: $(sort $(gb_Jar_KNOWN)),ALL))
-$$(eval $$(call gb_Output_error,Cannot link against jar $$(filter-out $(gb_Jar_KNOWN),$(2)). Jars must be registered in Repository.mk))
+$$(eval $$(call gb_Output_error,Cannot link against jar $$(filter-out $(gb_Jar_KNOWN),$(2)). Jars must be registered in Repository.mk or RepositoryExternal.mk))
 endif
 $(call gb_JavaClassSet_get_target,$(1)) : $(call gb_Jar_get_target,$(2))
 $(call gb_JavaClassSet_get_target,$(1)) : JARDEPS += $(call gb_Jar_get_target,$(2))

solenv/gbuild/Library.mk

@@ -51,7 +51,7 @@ define gb_Library_Library
 $(call gb_Postprocess_register_target,AllLibraries,Library,$(1))
 ifeq (,$$(findstring $(1),$$(gb_Library_KNOWNLIBS)))
 $$(eval $$(call gb_Output_info,Currently known libraries are: $(sort $(gb_Library_KNOWNLIBS)),ALL))
-$$(eval $$(call gb_Output_error,Library $(1) must be registered in Repository.mk))
+$$(eval $$(call gb_Output_error,Library $(1) must be registered in Repository.mk or RepositoryExternal.mk))
 endif
 
 $(if $(gb_Package_PRESTAGEDIR),\

solenv/gbuild/LinkTarget.mk

@@ -831,7 +831,7 @@ endef
 define gb_LinkTarget_use_libraries
 ifneq (,$$(filter-out $(gb_Library_KNOWNLIBS),$(2)))
 $$(eval $$(call gb_Output_info,currently known libraries are: $(sort $(gb_Library_KNOWNLIBS)),ALL))
-$$(eval $$(call gb_Output_error,Cannot link against library/libraries $$(filter-out $(gb_Library_KNOWNLIBS),$(2)). Libraries must be registered in Repository.mk))
+$$(eval $$(call gb_Output_error,Cannot link against library/libraries $$(filter-out $(gb_Library_KNOWNLIBS),$(2)). Libraries must be registered in Repository.mk or RepositoryExternal.mk))
 endif
 
 ifeq ($(call gb_LinkTarget__is_build_tool,$(1)),$(true))
@@ -1078,7 +1078,7 @@ endef
 define gb_LinkTarget_use_library_objects
 ifneq (,$$(filter-out $(gb_Library_KNOWNLIBS),$(2)))
 $$(eval $$(call gb_Output_info,currently known libraries are: $(sort $(gb_Library_KNOWNLIBS)),ALL))
-$$(eval $$(call gb_Output_error,Cannot import objects library/libraries $$(filter-out $(gb_Library_KNOWNLIBS),$(2)). Libraries must be registered in Repository.mk))
+$$(eval $$(call gb_Output_error,Cannot import objects library/libraries $$(filter-out $(gb_Library_KNOWNLIBS),$(2)). Libraries must be registered in Repository.mk or RepositoryExternal.mk))
 endif
 $(call gb_LinkTarget__use_linktarget_objects,$(1),$(foreach lib,$(2),$(call gb_Library_get_linktarget,$(lib))))
 $(call gb_LinkTarget_get_headers_target,$(1)) : \