custom build command fails if there's a space in the path

[rechade]

Hi, thanks for the crate!
I discovered a space in the path eg "/my projeck/..." causes compile to fail.
I renamed the path without a space and it compiles.

Running /my projeck/target/release/build/servo-fontconfig-sys-fa9d4f48edcf7cb9/build-script-build
error: failed to run custom build command for servo-fontconfig-sys v4.0.6

Caused by:
process didn't exit successfully: /my projeck/target/release/build/servo-fontconfig-sys-fa9d4f48edcf7 cb9/build-script-build (exit status: 101)
--- stdout
cargo:rerun-if-env-changed=FONTCONFIG_NO_PKG_CONFIG
cargo:rerun-if-env-changed=PKG_CONFIG
cargo:rerun-if-env-changed=FONTCONFIG_STATIC
cargo:rerun-if-env-changed=FONTCONFIG_DYNAMIC
cargo:rerun-if-env-changed=PKG_CONFIG_ALL_STATIC
cargo:rerun-if-env-changed=PKG_CONFIG_ALL_DYNAMIC
cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_PATH
cargo:rerun-if-env-changed=PKG_CONFIG_PATH
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_LIBDIR
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR
cd /my projeck/target/release/build/servo-fontconfig-sys-38824ed96a6e8b52/out &&
CC="gcc"
AR="ar"
FREETYPE_CFLAGS=""
FREETYPE_LIBS=""
CFLAGS=""" -fPIC"
/home/bob/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/servo-fontconfig-sys-4.0.6/configure

--disable-docs
--disable-shared

--host=x86_64-unknown-linux-gnu --sysconfdir=/etc --localstatedir=/var

--- stderr
makefile.cargo:83: warning: overriding recipe for target '/my'
makefile.cargo:61: warning: ignoring old recipe for target '/my'
make: Circular /my <- /my dependency dropped.
/bin/sh: 1: cd: can't cd to /my
make: *** [makefile.cargo:83: projectk/target/release/build/servo-fontconfig-sys-38824ed96a6e8b52/out/
Makefile] Error 2
thread 'main' panicked at 'assertion failed: Command::new("make").env("MAKEFLAGS",\n
env::var("CARGO_MAKEFLAGS").unwrap_or_default()).args(&["-R",\n
"-f",\n
"makefile.cargo"]).status().unwrap().success()', /home/bob/.c
argo/registry/src/git.luolix.top-1ecc6299db9ec823/servo-fontconfig-sys-4.0.6/build.rs:17:5
note: run with RUST_BACKTRACE=1 environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...
error: build failed