ww: import toolchain — C bootstrap + ww-side self-host (phases 0-10)

C bootstrap (phases 0-9):
  cmd/wwc, cmd/6c, cmd/6a, cmd/6l, cmd/ww, rt, lib/*.

ww-side self-host (phase 10):
  selfhost/cmd/wwc — ww-cgen frontend; bootstrap fixed point.
  selfhost/cmd/6a  — assembler; byte-identical to C 6a (test 991).
  selfhost/cmd/6l  — linker w/ archive (.a) support; byte-identical
                     to C 6l (test 992).
  selfhost/cmd/ww  — driver (build/run/version); byte-identical to
                     C ww (test 993).

make test: 15/15. make bootstrap: ww2.s == ww3.s, ww2.o == ww3.o,
ww2 == ww3 byte-identical, with the full ww-tooled chain.

test/wwc/900_stdlib.c

@@ -0,0 +1,65 @@
+/*
+ * 900_stdlib — verify each stdlib module parses, type-checks, and
+ * codegens. We don't link or run them; they exist for downstream
+ * users to import. As real applications come online they will start
+ * exercising the bodies through the e2e harness.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static const char *modules[] = {
+	"lib/types/types.ww",
+	"lib/ascii/ascii.ww",
+	"lib/bytes/bytes.ww",
+	"lib/strings/strings.ww",
+	"lib/io/stream.ww",
+	"lib/errors/errors.ww",
+	"lib/os/os.ww",
+	"lib/strconv/strconv.ww",
+	"lib/sort/sort.ww",
+	"lib/path/path.ww",
+	"lib/encoding/utf8/utf8.ww",
+	"lib/encoding/hex/hex.ww",
+	"lib/hash/fnv/fnv.ww",
+	"lib/time/time.ww",
+	"lib/c/libc/libc.ww",
+	"lib/bufio/bufio.ww",
+	"lib/fmt/fmt.ww",
+	"lib/net/net.ww",
+	"lib/slices/slices.ww",
+	NULL
+};
+
+int
+main(void)
+{
+	const char *bin = getenv("BIN");
+	if (!bin) bin = "out/bin";
+	char absbin[1024];
+	if (bin[0] != '/') {
+		char cwd[1024];
+		if (getcwd(cwd, sizeof cwd) == NULL) return 1;
+		snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
+		bin = absbin;
+	}
+	char cwd[1024];
+	if (getcwd(cwd, sizeof cwd) == NULL) return 1;
+
+	int n = 0, fail = 0;
+	for (int i = 0; modules[i]; i++, n++) {
+		char path[1024], cmd[2048];
+		snprintf(path, sizeof path, "%s/%s", cwd, modules[i]);
+		snprintf(cmd, sizeof cmd, "%s/6c %s > /dev/null 2>&1",
+		    bin, path);
+		int rc = system(cmd);
+		if (rc != 0) {
+			fprintf(stderr, "stdlib FAIL: %s (rc=%d)\n", modules[i], rc);
+			fail++;
+		}
+	}
+	if (fail) { fprintf(stderr, "%d/%d stdlib modules failed\n", fail, n); return 1; }
+	printf("stdlib: %d/%d ok\n", n, n);
+	return 0;
+}