Manual installation for Mac OS fails with permission denied.

Following https://github.com/Automattic/node-canvas/wiki/Installation%3A-Mac-OS-X#pkg-config

I run sudo ./configure --with-internal-glib && make install

But theres some sub script that runs and fails to install in usr/local/bin

Can I sudo the subscript somehow as well?

error:
....
Making install in libcharset
make[5]: Nothing to be done for `install-exec-am'.
make[5]: Nothing to be done for `install-data-am'.
Making install in gnulib
make[5]: Nothing to be done for `install-exec-am'.
make[5]: Nothing to be done for `install-data-am'.
Making install in .
echo > glib-public-headers.txt.tmp && mv glib-public-headers.txt.tmp glib-public-headers.txt
make[5]: Nothing to be done for `install-exec-am'.
make[5]: Nothing to be done for `install-data-am'.
Making install in .
./install-sh -c -d '/usr/local/bin'
/bin/sh ./libtool --mode=install /usr/bin/install -c pkg-config '/usr/local/bin'
libtool: install: /usr/bin/install -c pkg-config /usr/local/bin/pkg-config
install: /usr/local/bin/pkg-config: Permission denied
make[2]: *** [install-binPROGRAMS] Error 71
make[1]: *** [install-am] Error 2
make: *** [install-recursive] Error 1
## Steps to Reproduce

```bash
$ curl https://pkg-config.freedesktop.org/releases/pkg-config-0.28.tar.gz -o pkgconfig.tgz
$ tar -zxf pkgconfig.tgz && cd pkg-config-0.28
$ ./configure && make install
// etc.
```

I open a terminal at the folder location pkg-config-0.28 then run sudo ./configure --with-internal-glib && make install

## Your Environment
* Version of node-canvas (output of `npm list canvas` or `yarn list canvas`):
* Environment (e.g. node 4.2.0 on Mac OS X 10.8):