Cleanup code that we no longer use (rust-lang#768)

* Remove unused rustc code

We have modified the following files:
  - Cargo.toml: Remove all configuration that isn't needed.
  - Cargo.lock: Started from scratch

We have kept the following bookrunner dependencies:
  - src/docs
  - src/librustdocs
  - rustdoc-json-types

* Fix compile test source code check.

For some weird reason, compiletest checks the repository path by looking
at the path of a file. I just changed which file it looks for.

* Modified a few git configuration files

* Delete submodules

Author: celinval

.gitattributes

@@ -6,10 +6,7 @@
 *.rs rust diff=rust
 *.fixed linguist-language=Rust
 *.mir linguist-language=Rust
-src/etc/installer/gfx/* binary
-src/vendor/** -text
 Cargo.lock linguist-generated=false
-config.toml.example linguist-language=TOML
 
 # Older git versions try to fix line endings on images and fonts, this prevents it.
 *.png binary

.gitmodules

@@ -1,49 +1,24 @@
-[submodule "src/rust-installer"]
-	path = src/tools/rust-installer
-	url = https://github.com/rust-lang/rust-installer.git
 [submodule "src/doc/nomicon"]
 	path = src/doc/nomicon
 	url = https://github.com/rust-lang/nomicon.git
-[submodule "src/tools/cargo"]
-	path = src/tools/cargo
-	url = https://github.com/rust-lang/cargo.git
 [submodule "src/doc/reference"]
 	path = src/doc/reference
 	url = https://github.com/rust-lang/reference.git
 [submodule "src/doc/book"]
 	path = src/doc/book
 	url = https://github.com/rust-lang/book.git
-[submodule "src/tools/rls"]
-	path = src/tools/rls
-	url = https://github.com/rust-lang/rls.git
-[submodule "src/tools/miri"]
-	path = src/tools/miri
-	url = https://github.com/rust-lang/miri.git
 [submodule "src/doc/rust-by-example"]
 	path = src/doc/rust-by-example
 	url = https://github.com/rust-lang/rust-by-example.git
-[submodule "library/stdarch"]
-	path = library/stdarch
-	url = https://github.com/rust-lang/stdarch.git
 [submodule "src/doc/rustc-dev-guide"]
 	path = src/doc/rustc-dev-guide
 	url = https://github.com/rust-lang/rustc-dev-guide.git
 [submodule "src/doc/edition-guide"]
 	path = src/doc/edition-guide
 	url = https://github.com/rust-lang/edition-guide.git
-[submodule "src/llvm-project"]
-	path = src/llvm-project
-	url = https://github.com/rust-lang/llvm-project.git
-	branch = rustc/13.0-2021-09-30
 [submodule "src/doc/embedded-book"]
 	path = src/doc/embedded-book
 	url = https://github.com/rust-embedded/book.git
-[submodule "src/tools/rust-analyzer"]
-	path = src/tools/rust-analyzer
-	url = https://github.com/rust-analyzer/rust-analyzer.git
-[submodule "library/backtrace"]
-	path = library/backtrace
-	url = https://github.com/rust-lang/backtrace-rs.git
 [submodule "firecracker"]
 	path = firecracker
 	url = https://github.com/firecracker-microvm/firecracker.git