Use SpiderMonkey's encoding_c instead of our own crate

CMakeLists.txt

@@ -37,7 +37,7 @@ include("host_api")
 include("build-crates")
 
 add_library(extension_api INTERFACE include/extension-api.h runtime/encode.h)
-target_link_libraries(extension_api INTERFACE rust-url rust-encoding spidermonkey)
+target_link_libraries(extension_api INTERFACE rust-url spidermonkey)
 target_include_directories(extension_api INTERFACE include deps/include runtime)
 
 include("builtins")

cmake/build-crates.cmake

@@ -1,5 +1,2 @@
 corrosion_import_crate(MANIFEST_PATH ${CMAKE_CURRENT_SOURCE_DIR}/crates/rust-url/Cargo.toml NO_LINKER_OVERRIDE)
 set_property(TARGET rust-url PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_CURRENT_SOURCE_DIR}/crates/rust-url/)
-
-corrosion_import_crate(MANIFEST_PATH ${CMAKE_CURRENT_SOURCE_DIR}/crates/rust-encoding/Cargo.toml NO_LINKER_OVERRIDE)
-set_property(TARGET rust-encoding PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_CURRENT_SOURCE_DIR}/crates/rust-encoding/)

crates/rust-encoding/rust-encoding.h → deps/include/rust-encoding.h

@@ -1,3 +1,6 @@
+// NOTE: This file was generated by cbindgen for the encoding_c crate.
+// Since that crate is included in SpiderMonkey, we just include the header file here.
+// TODO: look into whether we can bundle the header file with SpiderMonkey's includes.
 // The constructor created by cbindgen's `derive_constructor` causes this warning.
 // Gecko's various uses of cbindgen silence it, so we do, too.
 #ifdef __clang__