gecko: unbreak RUST=on with cargo >= 0.18

error[E0463]: can't find crate for `cheddar`
 --> media/libstagefright/binding/mp4parse_capi/build.rs:1:1
  |
1 | extern crate cheddar;
  | ^^^^^^^^^^^^^^^^^^^^^ can't find crate

error: aborting due to previous error

fatal runtime error: failed to initiate panic, error 5
error: Could not compile `mp4parse_capi`.

Caused by:
  process didn't exit successfully: `/usr/local/bin/rustc --crate-name build_script_build media/libstagefright/binding/mp4parse_capi/build.rs --crate-type bin --emit=dep-info,link -C opt-level=2 -C debuginfo=2 -C metadata=13cd8b0152b68b4e -C extra-filename=-13cd8b0152b68b4e--out-dir obj-x86_64-unknown-freebsd12.0/toolkit/library/rust/./release/build/mp4parse_capi-13cd8b0152b68b4e -L dependency=obj-x86_64-unknown-freebsd12.0/toolkit/library/rust/./release/deps` (exit code: 1)
Build failed, waiting for other jobs to finish...
error: build failed

1 files changed, 66 insertions, 0 deletions

diff --git a/www/firefox-esr/files/patch-bug1338655 b/www/firefox-esr/files/patch-bug1338655
new file mode 100644
index 000000000000..d11c8114ea0d
--- /dev/null
+++ b/www/firefox-esr/files/patch-bug1338655
@@ -0,0 +1,66 @@
+commit bbd48a5613c8
+Author: Ralph Giles <giles@mozilla.com>
+Date:   Fri Feb 10 12:58:18 2017 -0800
+
+    Bug 1338655 - Don't try to build mp4parse bindings. r=froydnj
+    
+    We use the cheddar crate to generate a C header file
+    for our mp4parse_capi wrapper crate. Currently we
+    do this at code check-in time via update-rust.sh.
+    
+    Cargo 0.18 and later will try to execute a build.rs
+    file in the crate source tree regardless of whether
+    it's specified in Cargo.toml so patching out that
+    line just results in 'crate cheddar not found'.
+    
+    This change restores the old behaviour by substituting
+    a 'build = false' line instead.
+    
+    We do have syntex vendored, but we don't currently build
+    it by default, so I prefer this solution to just vendoring
+    cheddar and generating the header at build time. The syntex
+    crate is quite large and adds significantly to our compile
+    time.
+    
+    MozReview-Commit-ID: InJRRODWAdP
+    
+    --HG--
+    extra : rebase_source : 29378fcbc86015ce6cc22dc66d38a43ddbac204e
+---
+ media/libstagefright/binding/mp4parse-cargo.patch     | 5 +++--
+ media/libstagefright/binding/mp4parse_capi/Cargo.toml | 2 ++
+ 2 files changed, 5 insertions(+), 2 deletions(-)
+
+diff --git media/libstagefright/binding/mp4parse-cargo.patch media/libstagefright/binding/mp4parse-cargo.patch
+index 1dd13d20472a..bfa0ab74b424 100644
+--- media/libstagefright/binding/mp4parse-cargo.patch
++++ media/libstagefright/binding/mp4parse-cargo.patch
+@@ -25,12 +25,13 @@ diff --git a/media/libstagefright/binding/mp4parse_cap
+ index aeeebc65..5c0836a 100644
+ --- a/media/libstagefright/binding/mp4parse_capi/Cargo.toml
+ +++ b/media/libstagefright/binding/mp4parse_capi/Cargo.toml
+-@@ -18,17 +18,9 @@ exclude = [
++@@ -18,17 +18,11 @@ exclude = [
+    "*.mp4",
+  ]
+  
+ -build = "build.rs"
+--
+++build = false
++ 
+  [dependencies]
+  "mp4parse" = {version = "0.6.0", path = "../mp4parse"}
+  
+diff --git media/libstagefright/binding/mp4parse_capi/Cargo.toml media/libstagefright/binding/mp4parse_capi/Cargo.toml
+index aee7ee947151..d7e3f55119d3 100644
+--- media/libstagefright/binding/mp4parse_capi/Cargo.toml
++++ media/libstagefright/binding/mp4parse_capi/Cargo.toml
+@@ -18,6 +18,8 @@ exclude = [
+   "*.mp4",
+ ]
+ 
++build = false
++
+ [dependencies]
+ byteorder = "1.0.0"
+ "mp4parse" = {version = "0.6.0", path = "../mp4parse"}