allo system compiler

build.zig

@@ -1,9 +1,28 @@
 const std = @import("std");
 
-const c_lib = &[_][]const u8{ "tokenizer.c", "ast.c", "zig1.c" };
-const all_c_files = c_lib ++ &[_][]const u8{"main.c"};
+const c_lib_files = &[_][]const u8{ "tokenizer.c", "ast.c", "zig1.c" };
+const all_c_files = c_lib_files ++ &[_][]const u8{"main.c"};
+const cflags = &[_][]const u8{
+    "-std=c11",
+    "-Wall",
+    "-Wvla",
+    "-Wextra",
+    "-Werror",
+    "-Wshadow",
+    "-Wswitch",
+    "-Walloca",
+    "-Wformat=2",
+    "-fno-common",
+    "-Wconversion",
+    "-Wswitch-enum",
+    "-Wuninitialized",
+    "-Wdouble-promotion",
+    "-fstack-protector-all",
+    "-Wimplicit-fallthrough",
+    //"-D_FORTIFY_SOURCE=2", // consider when optimization flags are enabled
+};
 
-pub fn build(b: *std.Build) void {
+pub fn build(b: *std.Build) !void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
 
@@ -12,29 +31,31 @@ pub fn build(b: *std.Build) void {
         .optimize = optimize,
         .target = target,
     });
-    lib.addCSourceFiles(.{
-        .files = c_lib,
-        .flags = &[_][]const u8{
-            "-std=c11",
-            "-Wall",
-            "-Wvla",
-            "-Wextra",
-            "-Werror",
-            "-Wshadow",
-            "-Wswitch",
-            "-Walloca",
-            "-Wformat=2",
-            "-fno-common",
-            "-Wconversion",
-            "-Wswitch-enum",
-            "-Wuninitialized",
-            "-Wdouble-promotion",
-            "-fstack-protector-all",
-            "-Wimplicit-fallthrough",
-            //"-D_FORTIFY_SOURCE=2", // consider when optimization flags are enabled
-        },
-    });
-    lib.addIncludePath(b.path("."));
+
+    const cc = b.option([]const u8, "cc", "C compiler") orelse "zig";
+
+    if (std.mem.eql(u8, cc, "zig"))
+        lib.addCSourceFiles(.{ .files = c_lib_files, .flags = cflags })
+    else for (c_lib_files) |cfile| {
+        const objfile = try std.fmt.allocPrint(
+            b.allocator,
+            "{s}.o",
+            .{cfile[0 .. cfile.len - 2]},
+        );
+        const cc1 = b.addSystemCommand(&.{cc});
+        cc1.addArgs(cflags);
+        cc1.addArg("-g");
+        cc1.addArgs(switch (optimize) {
+            .Debug => &.{"-O0"},
+            .ReleaseFast, .ReleaseSafe => &.{"-O3"}, // TODO ubsan?
+            .ReleaseSmall => &.{"-Os"},
+        });
+        cc1.addArg("-c");
+        cc1.addFileArg(b.path(cfile));
+        cc1.addArg("-o");
+        const obj = cc1.addOutputFileArg(objfile);
+        lib.addObjectFile(obj);
+    }
     lib.linkLibC();
 
     const test_step = b.step("test", "Run unit tests");