rt: move slice append helpers from lib/slices/ into libwwrt.a

test/wcc/700_e2e.c

@@ -244,24 +244,10 @@ static const struct row rows[] = {
 	  "  x *= 2; x <<= 1; x >>= 2;\n"
 	  "  return x;\n"
 	  "};", 96 },
-	/* user-defined slice append via *[]u8: stdlib slices.appendu8.
-	 * Demonstrates allocator + ptr-to-slice fields + scaled index write. */
-	{ "use os;\n"
-	  "use slices;\n"
-	  "fn main() i32 = {\n"
-	  "  let s: []u8;\n"
-	  "  s.ptr = nil; s.len = 0; s.cap = 0;\n"
-	  "  slices.appendu8(&s, 65u8);\n"
-	  "  slices.appendu8(&s, 66u8);\n"
-	  "  slices.appendu8(&s, 67u8);\n"
-	  "  os.write(1, s.ptr, s.len: u64);\n"
-	  "  os.write(1, \"\\n\".ptr, 1u64);\n"
-	  "  return s.len;\n"
-	  "};", 3 },
 	/* Hare-style builtins: append(s, v) and len(s). The compiler
-	 * lowers these to slices.appendu8 / s.len access. */
+	 * lowers append to a CALL into libwwrt.a's appendu8 / appendi64
+	 * by element size — no `use rt;` or `use slices;` required. */
 	{ "use os;\n"
-	  "use slices;\n"
 	  "fn main() i32 = {\n"
 	  "  let s: []u8;\n"
 	  "  s.ptr = nil; s.len = 0; s.cap = 0;\n"
@@ -281,7 +267,6 @@ static const struct row rows[] = {
 	  "};", 12 },
 	/* variadic append + static qualifier (Hare idiom) */
 	{ "use os;\n"
-	  "use slices;\n"
 	  "fn main() i32 = {\n"
 	  "  let s: []u8;\n"
 	  "  s.ptr = nil; s.len = 0; s.cap = 0;\n"
@@ -298,7 +283,6 @@ static const struct row rows[] = {
 	  "};", 25 },
 	/* Hare-style range loop: for (let x .. slice) iterates elements */
 	{ "use os;\n"
-	  "use slices;\n"
 	  "fn main() i32 = {\n"
 	  "  let s: []u8;\n"
 	  "  s.ptr = nil; s.len = 0; s.cap = 0;\n"
@@ -309,7 +293,6 @@ static const struct row rows[] = {
 	  "};", 100 },
 	/* alloc([], n): fresh empty slice with cap n */
 	{ "use os;\n"
-	  "use slices;\n"
 	  "fn main() i32 = {\n"
 	  "  let s: []u8 = alloc([], 16);\n"
 	  "  append(s, 72u8, 105u8);\n"
@@ -317,7 +300,6 @@ static const struct row rows[] = {
 	  "};", 16 },
 	/* variadic spread: append(dst, src...) iterates src */
 	{ "use os;\n"
-	  "use slices;\n"
 	  "fn main() i32 = {\n"
 	  "  let src: []u8;\n"
 	  "  src.ptr = nil; src.len = 0; src.cap = 0;\n"

test/wcc/900_stdlib.c

@@ -28,7 +28,6 @@ static const char *modules[] = {
 	"lib/bufio/bufio.ww",
 	"lib/fmt/fmt.ww",
 	"lib/net/net.ww",
-	"lib/slices/slices.ww",
 	NULL
 };
 

test/wcc/990_selfhost.c

@@ -210,7 +210,6 @@ probe_dump_diff(const char *bin)
 		"lib/types/types.ww",
 		"lib/sort/sort.ww",
 		"lib/path/path.ww",
-		"lib/slices/slices.ww",
 		"lib/net/net.ww",
 		"lib/encoding/utf8/utf8.ww",
 		"lib/encoding/hex/hex.ww",