Support C3C_LIB and C3C_CC environment variables. Enable compiling against 20 to see if it works.

.github/workflows/main.yml

@@ -216,7 +216,7 @@ jobs:
       fail-fast: false
       matrix:
         build_type: [Release, Debug]
-        llvm_version: [17, 18, 19]
+        llvm_version: [17, 18, 19, 20]
 
     steps:
       - uses: actions/checkout@v4

releasenotes.md

@@ -9,6 +9,8 @@
 - Support `int[*] { 1, 2, 3 }` expressions.
 - Support inline struct designated init as if inline was anonymous.
 - Introduce the `.paramsof` property.
+- Support environment variable 'C3C_LIB' to find the standard library.
+- Support environment variable 'C3C_CC' to find the default C compiler.
 
 ### Fixes
 - Issue where a lambda wasn't correctly registered as external. #1408

src/compiler/compiler.c

@@ -270,6 +270,7 @@ static void free_arenas(void)
 static int compile_cfiles(const char *cc, const char **files, const char *flags, const char **include_dirs,
                           const char **out_files, const char *output_subdir)
 {
+	if (!cc) cc = default_c_compiler();
 	int total = 0;
 	FOREACH(const char *, file, files)
 	{
@@ -1453,3 +1454,20 @@ File *compile_and_invoke(const char *file, const char *args, const char *stdin_d
 	return source_file_text_load(file, out);
 }
 
+const char *default_c_compiler(void)
+{
+	static const char *cc = NULL;
+	if (cc) return cc;
+	const char *cc_env = getenv("C3C_CC");
+	if (cc_env && strlen(cc_env) > 0)
+	{
+		INFO_LOG("Setting CC to %s from environment variable 'C3C_CC'.", cc_env);
+		cc = strdup(cc);
+		return cc;
+	}
+#if PLATFORM_WINDOWS
+	return cc = "cl.exe";
+#else
+	return cc = "cc";
+#endif
+}

src/compiler/compiler_internal.h

@@ -3747,4 +3747,4 @@ INLINE bool check_module_name(Path *path)
 	return true;
 }
 
-
+const char *default_c_compiler(void);

src/compiler/linker.c

@@ -853,7 +853,7 @@ void platform_linker(const char *output_file, const char **files, unsigned file_
 	else
 	{
 		INFO_LOG("Using cc linker.");
-		vec_add(parts, compiler.build.cc ? compiler.build.cc : "cc");
+		vec_add(parts, compiler.build.cc ? compiler.build.cc : default_c_compiler());
 		append_fpie_pic_options(compiler.platform.reloc_model, &parts);
 	}
 

src/compiler/target.c

@@ -1931,10 +1931,6 @@ void target_setup(BuildTarget *target)
 		default:
 			break;
 	}
-	if (!target->cc)
-	{
-		target->cc = compiler.platform.os == OS_TYPE_WIN32 ? "cl.exe" : "cc";
-	}
 
 	compiler.platform.int128 = os_target_supports_int128(compiler.platform.os, compiler.platform.arch);
 	compiler.platform.vec128f = os_target_supports_vec(compiler.platform.os, compiler.platform.arch, 128, false);

src/utils/file_utils.c

@@ -184,8 +184,6 @@ bool file_namesplit(const char *path, char** filename_ptr, char** directory_ptr)
 	return true;
 }
 
-
-
 const char *file_expand_path(const char *path)
 {
 	if (path[0] == '~' && path[1] == '/')
@@ -377,6 +375,16 @@ const char *find_rel_exe_dir(const char *dir)
 
 const char *find_lib_dir(void)
 {
+	char *lib_dir_env = getenv("C3C_LIB");
+	if (lib_dir_env && strlen(lib_dir_env) > 0)
+	{
+		INFO_LOG("Using stdlib library from env 'C3C_LIB': %s.", lib_dir_env);
+		if (!file_exists(lib_dir_env))
+		{
+			error_exit("Library path from 'C3C_LIB' environment variable: '%s', could not be resolved.", lib_dir_env);
+		}
+		return strdup(lib_dir_env);
+	}
 	char *path = find_executable_path();
 
 	INFO_LOG("Detected executable path at %s", path);