write a CI workflow for multiple OSes, that compile and test the code using the makefile.

this is the most portable and clean approach. Compiler built-ins should
always be present regardless, and is more maintainable, since we're not
trying to keep up with various versions of this header.

.github/workflows/ci.yaml

@@ -0,0 +1,30 @@
+name: CI
+on:
+  push:
+    branches: [main]
+
+jobs:
+  compile-and-test:
+    strategy:
+      matrix:
+        os:
+          - ubuntu-latest
+          - ubuntu-24.04-arm
+          - windows-latest
+          - windows-11-arm
+          - macos-latest
+    runs-on: ${{matrix.os}}
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          repository: ${{github.repository}}
+          submodules: true
+          fetch-depth: 1
+      - uses: actions/cache@v4
+        with:
+          path: lib/obj/
+          key: ${{runner.os}}-lib/obj-${{github.sha}}
+          restore-keys: ${{runner.os}}-lib/obj-
+      - run: make libs
+      - run: make all
+      - run: make test

Makefile

@@ -35,13 +35,13 @@ $(warning Detected Windows_NT, please refer to the documentation if you encounte
 endif
 
 # TODO: find a better method to find all source files
-# WARN: find a better method for selecting the object files
 # find all the source files using wildcards
 # NOTE: MS-DOS and MS-Windows uses backslash `\`, this might break.
-RES  := $(wildcard res/*.glsl)
-SRC  := $(wildcard src/*.c  src/*/*.c  src/*/*/*.c  src/*/*/*/*.c  src/*/*/*/*/*.c  src/*/*/*/*/*/*.c  src/*/*/*/*/*/*/*.c  src/*/*/*/*/*/*/*/*.c) lib/glad/gl.c
-OBJ  := $(SRC:%.c=obj/%.o)
-TEST := $(wildcard test/*.c test/*/*.c test/*/*/*.c test/*/*/*/*.c test/*/*/*/*/*.c test/*/*/*/*/*/*.c test/*/*/*/*/*/*/*.c test/*/*/*/*/*/*/*/*.c)
+RES  := $(wildcard res/*)
+SRC  := $(wildcard src/*.c src/*/*.c src/*/*/*.c src/*/*/*/*.c src/*/*/*/*/*.c src/*/*/*/*/*/*.c src/*/*/*/*/*/*/*.c src/*/*/*/*/*/*/*/*.c) lib/glad/gl.c
+OBJ  := $(SRC:%.c=obj/%.o) $(RES:%=obj/%.o)
+TSRC := $(wildcard test/*.c test/*/*.c test/*/*/*.c test/*/*/*/*.c test/*/*/*/*/*.c test/*/*/*/*/*/*.c test/*/*/*/*/*/*/*.c test/*/*/*/*/*/*/*/*.c)
+TOBJ := $(TSRC:%.c=obj/%.o)
 
 # TODO: potentially automatically detect whether we should compile libs, or if we can just go ahead.
 .PHONY: all libs test clean clean-libs
@@ -67,8 +67,7 @@ bin/$(NAME): $(OBJ)
 	@$(CC) -o $@ $^ $(LDFLAGS) $(LDLIBS)
 
 # link together a testing binary
-# BUG: testing sources must be selected better
-bin/TEST_$(NAME): $(OBJ)
+bin/TEST_$(NAME): $(TOBJ) $(filter-out main.o,$(OBJ))
 	$(info [CC/LD]	$@)
 	@mkdir -p $(@D)
 	@$(CC) -o $@ $^ $(LDFLAGS) $(LDLIBS)

include/endian.h

@@ -1,46 +1,9 @@
 /* Copyright (c) 2025 Quinn
  * Licensed under the MIT Licence. See LICENSE for details */
-
 #ifndef PORTABLE_ENDIAN_H
 #define PORTABLE_ENDIAN_H 1
 
 #if defined(__GNUC__)
-
-/* test for the byteswap header */
-#if __has_include(<byteswap.h>)
-#include <byteswap.h>
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-#define le16toh(x) (x)
-#define le32toh(x) (x)
-#define le64toh(x) (x)
-#define htole16(x) (x)
-#define htole32(x) (x)
-#define htole64(x) (x)
-#define be16toh(x) bswap_16(x)
-#define be32toh(x) bswap_32(x)
-#define be64toh(x) bswap_64(x)
-#define htobe16(x) bswap_16(x)
-#define htobe32(x) bswap_32(x)
-#define htobe64(x) bswap_64(x)
-#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-#define le16toh(x) bswap_16(x)
-#define le32toh(x) bswap_32(x)
-#define le64toh(x) bswap_64(x)
-#define htole16(x) bswap_16(x)
-#define htole32(x) bswap_32(x)
-#define htole64(x) bswap_64(x)
-#define be16toh(x) (x)
-#define be32toh(x) (x)
-#define be64toh(x) (x)
-#define htobe16(x) (x)
-#define htobe32(x) (x)
-#define htobe64(x) (x)
-#else
-#error machine architecture unsupported! Expected either big-endian or little-endian, make sure to use a compiler which defines __BYTE_ORDER__ (like clang or gcc)
-#endif /* byte order */
-
-/* otherwise, utilise the compiler built-ins */
-#else
 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 #define le16toh(x) __uint16_identity(x)
 #define le32toh(x) __uint32_identity(x)
@@ -71,10 +34,7 @@
 #error machine architecture unsupported! Expected either big-endian or little-endian, make sure to use a compiler which defines __BYTE_ORDER__ (like clang or gcc)
 #endif /* byte order */
 
-#endif /* has byteswap.h */
-
 #else
 #error GNU C is unavailable
 #endif /* __GNUC__ */
-
 #endif /* PORTABLE_ENDIAN_H */