Update emscripten include dir to v18
diff --git a/bazel/emscripten_toolchain/toolchain.bzl b/bazel/emscripten_toolchain/toolchain.bzl
index f1ea1c8..e92a612 100644
--- a/bazel/emscripten_toolchain/toolchain.bzl
+++ b/bazel/emscripten_toolchain/toolchain.bzl
@@ -914,7 +914,7 @@
                 "-iwithsysroot" + "/include/compat",
                 "-iwithsysroot" + "/include",
                 "-isystem",
-                emscripten_dir + "/lib/clang/17/include",
+                emscripten_dir + "/lib/clang/18/include",
             ],
         ),
         # Inputs and outputs
@@ -1081,7 +1081,7 @@
         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/17/include",
+        emscripten_dir + "/lib/clang/18/include",
     ]
 
     artifact_name_patterns = []