pkg-config is needed for compilation.

See: https://github.com/01org/dynamic-application-loader-host-interface/issues/2#issuecomment-306074645

Signed-off-by: Mi Tar <mitar.github@tnode.com>

README.md

@@ -203,7 +203,7 @@ Install Intel(R) SGX PSW
   Download source code from [dynamic-application-loader-host-interface](https://github.com/01org/dynamic-application-loader-host-interface) project. In the source code folder build and install JHI service using the following commands:
   * On Ubuntu 16.04:
   ```
-    $ sudo apt-get install uuid-dev libxml2-dev cmake
+    $ sudo apt-get install uuid-dev libxml2-dev cmake pkg-config
     $ cmake .;make;sudo make install;sudo systemctl enable jhi
   ```
   * On Red Hat Enterprise Linux 7.2 and CentOS 7.3: