Adapt the shipped rust-bindgen copy for LLVM-18 and later,
and tell cargo we've modified the code of rust-bindgen so
the checksum verification of this crate should be skipped

diff -rup a/Cargo.lock b/Cargo.lock
--- a/Cargo.lock        2024-03-14 06:21:23.000000000 +0100
+++ b/Cargo.lock        2024-03-20 13:15:35.146224179 +0100
@@ -414,8 +414,8 @@ dependencies = [
 [[package]]
 name = "bindgen"
 version = "0.64.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c4243e6031260db77ede97ad86c27e501d646a27ab57b59a574f725d98ab1fb4"
+#source = "registry+https://github.com/rust-lang/crates.io-index"
+#checksum = "c4243e6031260db77ede97ad86c27e501d646a27ab57b59a574f725d98ab1fb4"
 dependencies = [
  "bitflags 1.3.2",
  "cexpr",
diff -rup a/Cargo.toml b/Cargo.toml
--- a/Cargo.toml        2024-03-20 13:09:16.152828408 +0100
+++ b/Cargo.toml        2024-03-20 13:14:09.072867031 +0100
@@ -193,3 +193,8 @@ weedle2 = "=4.0.0"
 # Shut up such messages for now to make the build succeed
 [future-incompat-report]
 frequency = "never"
+
+[patch.crates-io.bindgen_0_64_0]
+package = "bindgen"
+version = "0.64.0"
+path = "third_party/rust/bindgen"
diff -rup a/third_party/rust/bindgen/ir/item.rs b/third_party/rust/bindgen/ir/item.rs
--- a/third_party/rust/bindgen/ir/item.rs        2024-03-14 06:21:40.000000000 +0100
+++ b/third_party/rust/bindgen/ir/item.rs        2024-03-20 13:11:32.062844514 +0100
@@ -1434,6 +1434,7 @@ impl Item {
             // We allowlist cursors here known to be unhandled, to prevent being
             // too noisy about this.
             match cursor.kind() {
+                CXCursor_LinkageSpec => return Err(ParseError::Recurse),
                 CXCursor_MacroDefinition |
                 CXCursor_MacroExpansion |
                 CXCursor_UsingDeclaration |


Adapt the WebRTC code to use 64-bit timestamp to fix a build
failure with Clang-18 and later

diff -rup a/dom/media/gmp-plugin-openh264/gmp-fake-openh264.cpp b/dom/media/gmp-plugin-openh264/gmp-fake-openh264.cpp
--- a/dom/media/gmp-plugin-openh264/gmp-fake-openh264.cpp        2024-03-14 06:21:25.000000000 +0100
+++ b/dom/media/gmp-plugin-openh264/gmp-fake-openh264.cpp        2024-03-20 13:17:20.839584778 +0100
@@ -99,7 +99,7 @@ struct EncodedFrame {
     uint8_t y_;
     uint8_t u_;
     uint8_t v_;
-    uint32_t timestamp_;
+    uint64_t timestamp_;
   } idr_nalu;
 };
 #pragma pack(pop)
diff -rup a/dom/media/gtest/TestGMPRemoveAndDelete.cpp b/dom/media/gtest/TestGMPRemoveAndDelete.cpp
--- a/dom/media/gtest/TestGMPRemoveAndDelete.cpp        2024-03-14 06:21:25.000000000 +0100
+++ b/dom/media/gtest/TestGMPRemoveAndDelete.cpp        2024-03-20 13:17:20.839584778 +0100
@@ -361,7 +361,7 @@ void GMPRemoveTest::gmp_Decode() {
       uint8_t y_;
       uint8_t u_;
       uint8_t v_;
-      uint32_t timestamp_;
+      uint64_t timestamp_;
     } idr_nalu;
   };
 #pragma pack(pop)
diff -rup a/dom/media/webrtc/libwebrtcglue/WebrtcGmpVideoCodec.cpp b/dom/media/webrtc/libwebrtcglue/WebrtcGmpVideoCodec.cpp
--- a/dom/media/webrtc/libwebrtcglue/WebrtcGmpVideoCodec.cpp        2024-03-14 06:21:24.000000000 +0100
+++ b/dom/media/webrtc/libwebrtcglue/WebrtcGmpVideoCodec.cpp        2024-03-20 13:17:20.842918112 +0100
@@ -540,7 +540,7 @@ void WebrtcGmpVideoEncoder::Encoded(
 
   webrtc::VideoFrameType ft;
   GmpFrameTypeToWebrtcFrameType(aEncodedFrame->FrameType(), &ft);
-  uint32_t timestamp = (aEncodedFrame->TimeStamp() * 90ll + 999) / 1000;
+  uint64_t timestamp = (aEncodedFrame->TimeStamp() * 90ll + 999) / 1000;
 
   GMP_LOG_DEBUG("GMP Encoded: %" PRIu64 ", type %d, len %d",
                 aEncodedFrame->TimeStamp(), aEncodedFrame->BufferType(),
diff -rup a/dom/media/webrtc/libwebrtcglue/WebrtcGmpVideoCodec.h b/dom/media/webrtc/libwebrtcglue/WebrtcGmpVideoCodec.h
--- a/dom/media/webrtc/libwebrtcglue/WebrtcGmpVideoCodec.h        2024-03-14 06:21:24.000000000 +0100
+++ b/dom/media/webrtc/libwebrtcglue/WebrtcGmpVideoCodec.h        2024-03-20 13:17:32.442921055 +0100
@@ -302,7 +302,7 @@ class WebrtcGmpVideoEncoder : public GMP
     int64_t timestamp_us;
   };
   // Map rtp time -> input image data
-  DataMutex<std::map<uint32_t, InputImageData>> mInputImageMap;
+  DataMutex<std::map<uint64_t, InputImageData>> mInputImageMap;
 
   MediaEventProducer<uint64_t> mInitPluginEvent;
   MediaEventProducer<uint64_t> mReleasePluginEvent;