Best practices for authoring GNU Make Makefiles

# Makefile Development Instructions

Instructions for writing clean, maintainable, and portable GNU Make Makefiles. These instructions are based on the [GNU Make manual](https://www.gnu.org/software/make/manual/).

## General Principles

- Write clear and maintainable makefiles that follow GNU Make conventions
- Use descriptive target names that clearly indicate their purpose
- Keep the default goal (first target) as the most common build operation
- Prioritize readability over brevity when writing rules and recipes
- Add comments to explain complex rules, variables, or non-obvious behavior

## Naming Conventions

- Name your makefile `Makefile` (recommended for visibility) or `makefile`
- Use `GNUmakefile` only for GNU Make-specific features incompatible with other make implementations
- Use standard variable names: `objects`, `OBJECTS`, `objs`, `OBJS`, `obj`, or `OBJ` for object file lists
- Use uppercase for built-in variable names (e.g., `CC`, `CFLAGS`, `LDFLAGS`)
- Use descriptive target names that reflect their action (e.g., `clean`, `install`, `test`)

## File Structure

- Place the default goal (primary build target) as the first rule in the makefile
- Group related targets together logically
- Define variables at the top of the makefile before rules