Compile error on macOS

[bjorn3]

$ cargo build
   Compiling fontsan v0.3.2 (https://github.com/servo/fontsan#ab68da17)
error: failed to run custom build command for `fontsan v0.3.2 (https://github.com/servo/fontsan#ab68da17)`
process didn't exit successfully: `$SERVO/target/debug/build/fontsan-abde3c64f4ae00be/build-script-build` (exit code: 101)
--- stdout
running: "cmake" "$HOME/.cargo/git/checkouts/fontsan-75864180be477bc9/ab68da1/src" "-DCMAKE_INSTALL_PREFIX=$SERVO/target/debug/build/fontsan-58f875ff64dc5050/out" "-DCMAKE_C_FLAGS= -ffunction-sections -fdata-sections -m64 -fPIC" "-DCMAKE_C_COMPILER=/usr/bin/cc" "-DCMAKE_CXX_FLAGS= -ffunction-sections -fdata-sections -m64 -fPIC" "-DCMAKE_CXX_COMPILER=/usr/bin/c++" "-DCMAKE_BUILD_TYPE=Debug"
-- Configuring done
-- Generating done
-- Build files have been written to: $SERVO/target/debug/build/fontsan-58f875ff64dc5050/out/build

--- stderr
CMake Error at CMakeLists.txt:119 (add_library):
  Cannot find source file:

    ots/third_party/woff2/src/buffer.h

  Tried extensions .c .C .c++ .cc .cpp .cxx .m .M .mm .h .hh .h++ .hm .hpp
  .hxx .in .txx


CMake Error at CMakeLists.txt:118 (add_library):
  Cannot find source file:

    ots/third_party/brotli/dec/decode.h

  Tried extensions .c .C .c++ .cc .cpp .cxx .m .M .mm .h .hh .h++ .hm .hpp
  .hxx .in .txx


CMake Error: Cannot determine link language for target "woff2".
CMake Error: CMake can not determine linker language for target: woff2
CMake Error: Cannot determine link language for target "brotli".
CMake Error: CMake can not determine linker language for target: brotli
thread 'main' panicked at '
command did not execute successfully, got: exit code: 1

build script failed, must exit now', $HOME/.cargo/registry/src/github.com-1ecc6299db9ec823/cmake-0.1.20/src/lib.rs:573
stack backtrace:
   1:        0x1059a082c - std::sys::imp::backtrace::tracing::imp::write::h36c82bddc32ee014
   2:        0x1059a5ede - std::panicking::default_hook::{{closure}}::h5befc2c9c6395cdf
   3:        0x1059a5b80 - std::panicking::default_hook::hc066c0e0f8dcf194
   4:        0x1059a62e6 - std::panicking::rust_panic_with_hook::hb2f44ed7df6389fd
   5:        0x1059a6184 - std::panicking::begin_panic::h98e44359ade7bd0a
   6:        0x1059a60a2 - std::panicking::begin_panic_fmt::hb5af1180f1c36e1d
   7:        0x105976207 - cmake::fail::hb42b440447d4f2a1
   8:        0x105975a43 - cmake::run::h07147df591eb4294
   9:        0x105972321 - cmake::Config::build::h0593fb88e2945326
  10:        0x10595965c - build_script_build::main::he1da3c99c17e71e3
  11:        0x1059a8cfa - __rust_maybe_catch_panic
  12:        0x1059a6696 - std::rt::lang_start::hba46b5e984e5d783
  13:        0x105959999 - main

[zfogg]

@bjorn3 was suffering from this too and figured out how to fix it:

git submodule update --init --recursive

[bjorn3]

Where do I need to run it? Still can't compile after running it in the servo root dir.