Hace::MakefileConverter

Converts basic GNU Makefiles into Hacefile.yml content.

Supported subset:

• rules with prerequisites and tab-indented recipes
• multiple targets per rule (become multiple outputs)
• variables (=, :=, ::=, ?=, +=), with $(NAME) / ${NAME} references. Variable values are resolved eagerly (make's "undefined means empty" semantics apply, and recursive variables must be defined before use).
• export VAR=value becomes an env: entry
• a SHELL variable becomes the Hacefile shell: setting
• .PHONY and .DEFAULT_GOAL
• automatic variables: $@ $< $^ $? $* and $$ escaping
• pattern rules ("%.o: %.c"), emitted into a patterns: section

Anything else (conditionals, functions like $(wildcard), include, target-specific variables, static pattern rules, ...) produces a warning and is skipped; conversion never aborts because of unsupported constructs.