lib directory does not exist on Windows custom

[ctaggart]

C:\Users\camer\rs\chakracore-rs\chakracore-sys>echo %CHAKRA_SOURCE%
C:\Users\camer\rs\ChakraCore

C:\Users\camer\rs\chakracore-rs\chakracore-sys>echo %CHAKRA_BUILD%
C:\Users\camer\rs\ChakraCore\Build\VcBuild\bin\x64_release

C:\Users\camer\rs\chakracore-rs\chakracore-sys>cargo test -vv
       Fresh unicode-width v0.1.4
       Fresh utf8-ranges v1.0.0
       Fresh rustc-serialize v0.3.24
       Fresh unicode-segmentation v1.2.0
       Fresh log v0.3.8
       Fresh glob v0.2.11
       Fresh bitflags v0.8.2
       Fresh cfg-if v0.1.2
       Fresh unicode-xid v0.0.4
       Fresh regex-syntax v0.4.1
       Fresh void v1.0.2
       Fresh bitflags v0.9.1
       Fresh winapi-build v0.1.1
       Fresh ansi_term v0.9.0
       Fresh winapi v0.2.8
       Fresh peeking_take_while v0.1.2
       Fresh lazy_static v0.2.8
       Fresh libc v0.2.29
       Fresh strsim v0.6.0
       Fresh pkg-config v0.3.9
       Fresh vec_map v0.8.0
       Fresh syntex_pos v0.58.1
       Fresh unreachable v1.0.0
       Fresh memchr v1.0.1
       Fresh thread_local v0.3.4
       Fresh nom v3.2.0
       Fresh aho-corasick v0.6.3
       Fresh kernel32-sys v0.2.2
       Fresh cexpr v0.2.2
       Fresh regex v0.2.2
       Fresh term v0.4.6
       Fresh atty v0.2.2
       Fresh term_size v0.3.0
       Fresh libloading v0.4.0
       Fresh env_logger v0.4.3
       Fresh syntex_errors v0.58.1
       Fresh textwrap v0.7.0
       Fresh clang-sys v0.18.0
       Fresh syntex_syntax v0.58.1
       Fresh clap v2.26.0
       Fresh aster v0.41.0
       Fresh quasi v0.32.0
       Fresh syntex v0.58.1
       Fresh quasi_codegen v0.32.0
       Fresh bindgen v0.25.5
   Compiling chakracore-sys v0.2.2 (file:///C:/Users/camer/rs/chakracore-rs/chakracore-sys)
     Running `C:\Users\camer\rs\chakracore-rs\chakracore-sys\target\debug\build\chakracore-sys-386c670e5139aed9\build-script-build`
cargo:rerun-if-env-changed=CHAKRA_SOURCE
cargo:rerun-if-env-changed=CHAKRA_BUILD
chakracore-sys/build.rs:48: Using custom ChakraCore build
thread 'main' panicked at 'Library search path '"C:\\Users\\camer\\rs\\ChakraCore\\Build\\VcBuild\\bin\\x64_release\\lib"' does not exist', build.rs:234
stack backtrace:
   0: std::sys_common::backtrace::_print
             at C:\projects\rust\src\libstd\sys_common\backtrace.rs:71
   1: std::panicking::default_hook::{{closure}}
             at C:\projects\rust\src\libstd\panicking.rs:354
   2: std::panicking::default_hook
             at C:\projects\rust\src\libstd\panicking.rs:371
   3: std::panicking::rust_panic_with_hook
             at C:\projects\rust\src\libstd\panicking.rs:549
   4: std::panicking::begin_panic<collections::string::String>
             at C:\projects\rust\src\libstd\panicking.rs:511
   5: build_script_build::linking::add_path<&std::path::PathBuf>
             at .\build.rs:234
   6: build_script_build::linking::setup
             at .\build.rs:194
   7: build_script_build::main
             at .\build.rs:56
   8: panic_unwind::__rust_maybe_catch_panic
             at C:\projects\rust\src\libpanic_unwind\lib.rs:98
   9: std::rt::lang_start
             at C:\projects\rust\src\libstd\rt.rs:52
  10: main
  11: __scrt_common_main_seh
             at f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:283
  12: BaseThreadInitThunk
error: failed to run custom build command for `chakracore-sys v0.2.2 (file:///C:/Users/camer/rs/chakracore-rs/chakracore-sys)`
process didn't exit successfully: `C:\Users\camer\rs\chakracore-rs\chakracore-sys\target\debug\build\chakracore-sys-386c670e5139aed9\build-script-build` (exit code: 101)
--- stdout
cargo:rerun-if-env-changed=CHAKRA_SOURCE
cargo:rerun-if-env-changed=CHAKRA_BUILD
chakracore-sys/build.rs:48: Using custom ChakraCore build

--- stderr
thread 'main' panicked at 'Library search path '"C:\\Users\\camer\\rs\\ChakraCore\\Build\\VcBuild\\bin\\x64_release\\lib"' does not exist', build.rs:234
stack backtrace:
   0: std::sys_common::backtrace::_print
             at C:\projects\rust\src\libstd\sys_common\backtrace.rs:71
   1: std::panicking::default_hook::{{closure}}
             at C:\projects\rust\src\libstd\panicking.rs:354
   2: std::panicking::default_hook
             at C:\projects\rust\src\libstd\panicking.rs:371
   3: std::panicking::rust_panic_with_hook
             at C:\projects\rust\src\libstd\panicking.rs:549
   4: std::panicking::begin_panic<collections::string::String>
             at C:\projects\rust\src\libstd\panicking.rs:511
   5: build_script_build::linking::add_path<&std::path::PathBuf>
             at .\build.rs:234
   6: build_script_build::linking::setup
             at .\build.rs:194
   7: build_script_build::main
             at .\build.rs:56
   8: panic_unwind::__rust_maybe_catch_panic
             at C:\projects\rust\src\libpanic_unwind\lib.rs:98
   9: std::rt::lang_start
             at C:\projects\rust\src\libstd\rt.rs:52
  10: main
  11: __scrt_common_main_seh
             at f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:283

To get past this error, I did mkdir %CHAKRA_BUILD%\lib.