gnu-make

This skill should be used when the user asks about Makefile pattern rules, automatic variables ($@, $<, $^, $?, $*), wildcard functions, patsubst, reducing Makefile duplication, compiling multiple C files with one rule, static pattern rules, conditional compilation with ifeq, or target-specific variables. Also applies when the user shows repetitive explicit rules that could be replaced with pattern rules, or asks about DRY Makefile practices. For basic Makefile creation and the ## help pattern, see makefile-fundamentals.

This skill should be used when the user asks to debug a Makefile, diagnose slow builds, fix unexpected rebuild behavior, understand why make rebuilds everything, figure out why a target does not rebuild, check Makefile variable values, use make -n/-d/-p/--trace flags, optimize build performance, or troubleshoot any Makefile issue. Also applies when the user reports "build is slow", "everything rebuilds", or "target never rebuilds".

This skill should be used when the user asks to create a Makefile, write a Makefile, generate a Makefile template, fix a broken Makefile, resolve a "missing separator" error, add build targets, set up a help target, or implement self-documenting Makefiles with the ## comment pattern. Also applies when reviewing Makefiles for best practices like .PHONY declarations, tab characters, and .DELETE_ON_ERROR. For pattern rules and automatic variables in depth, see the makefile-advanced-features skill.

This skill should be used when the user asks about splitting a Makefile into multiple files, using the include or -include directive, organizing a large Makefile into modules, creating environment-specific configurations (dev/prod/staging), sharing Makefile configuration across projects, or when a Makefile exceeds 150 lines. Also applies when the user mentions config.mk, rules.mk, modular Makefile structure, or asks how to reduce Makefile size and improve maintainability.

This skill should be used when the user asks about multi-directory Makefile builds, recursive make, building subdirectories, using make -C, structuring a project with multiple Makefiles, fixing make -j parallelism issues, replacing shell loops with phony targets, exporting variables to sub-makes, or using the $(MAKE) variable. Also applies when the user shows a for-loop pattern in a root Makefile for building subdirectories.