Print nice error message when python is not installed
If user runs `make help` on a system without python, we should print a
decent message.
@@ -135,8 +135,13 @@ export PRINT_HELP_PYSCRIPT
err_if_empty = $(if $(strip $($(1))),$(strip $($(1))),$(error Required variable $(1) value is undefined, whitespace, or empty))
.PHONY: help
+ifneq (, ${PYTHON})
help:
@$(PYTHON) -c "$$PRINT_HELP_PYSCRIPT" < $(MAKEFILE_LIST)
+else
+help:
+ $(error python required for 'make help', executable not found)
+endif
.gopathok:
ifeq ("$(wildcard $(GOPKGDIR))","")
