Release 4.0.2 (#1516)

With emscripten-releases revisions:

https://chromium.googlesource.com/emscripten-releases/+/cc8eba40de8235f9c33d92463018f87b3edaa09e
(LTO)

https://chromium.googlesource.com/emscripten-releases/+/dc575ac9a214463b2b3503c11a1a31db665b4414
(asserts)

---------

Co-authored-by: Sam Clegg <sbc@chromium.org>

bazel/emscripten_toolchain/toolchain.bzl

@@ -934,7 +934,7 @@ def _impl(ctx):
                 "-iwithsysroot" + "/include/compat",
                 "-iwithsysroot" + "/include",
                 "-isystem",
-                emscripten_dir + "/lib/clang/20/include",
+                emscripten_dir + "/lib/clang/21/include",
             ],
         ),
         # Inputs and outputs
@@ -1101,7 +1101,7 @@ def _impl(ctx):
         emscripten_dir + "/emscripten/cache/sysroot/include/c++/v1",
         emscripten_dir + "/emscripten/cache/sysroot/include/compat",
         emscripten_dir + "/emscripten/cache/sysroot/include",
-        emscripten_dir + "/lib/clang/20/include",
+        emscripten_dir + "/lib/clang/21/include",
     ]
 
     artifact_name_patterns = []

bazel/revisions.bzl

@@ -2,6 +2,13 @@
 # DO NOT MODIFY
 
 EMSCRIPTEN_TAGS = {
+    "4.0.2": struct(
+        hash = "cc8eba40de8235f9c33d92463018f87b3edaa09e",
+        sha_linux = "3c0e3940240709388c24a4262680c18bb1d5979f2337abe53db00fb039606c44",
+        sha_mac = "e1bd96ec790968adf583d348158375b76ee0287e348954c3393c82565475b07b",
+        sha_mac_arm64 = "e5bf9a5efabc114b42636abcea07a1e02d3a9406cd399a29ccbc730586dce465",
+        sha_win = "78010f8e2f7bb6868bb20e3fc32e24d45e6fca749c388c2d25bea9845512338d",
+    ),
     "4.0.1": struct(
         hash = "5ff495a591978fdf8a16f2d172be3616f3150d1e",
         sha_linux = "7b2b64b1bc15555696f78cbcb54c8d75832222d1578270ff5f56a8024c9a0dbc",