Minor improvement

Summary: Just making this coherent with the instructions in the other `building_for_...` documents

Reviewed By: janherling

Differential Revision: D59527723

fbshipit-source-id: 9d618293b9b2fab7ca1513d39f749b8851dfb32a

building_for_macos.md

@@ -17,6 +17,7 @@ This document describes the process to build Ocean for macOS. It covers:
 The easiest way to build the third-party libraries is by using the provided build script, [`build/cmake/build_thirdparty_linuxunix.sh`](build/cmake/build_thirdparty_linuxunix.sh). By default, this will build all third-party libraries in both debug and release configurations. Each of these will be built with static as well as dynamic linking. To build a specific configuration, use the parameters `--config BUILD_TYPE` and `--link LINKING_TYPE`. For example to build only the static debug and release configurations, run:
 
 ```
+cd ${OCEAN_DEVELOPMENT_PATH}
 ./build/cmake/build_thirdparty_linuxunix.sh -c debug,release -l static -b "${HOME}/build_ocean_thirdparty" -i "${HOME}/install_ocean_thirdparty"
 ```