The uname executable for OSX does not recognize the ~~o parameter and results in a warning when creating a new Android project:
uname: illegal option — o
./create-android-project.sh: line 23: [: =: unary operator expected
The manpage for uname states for the~~o parameter: _This is a synonym for the ~~s option, for compatibility with other systems._
Therefore, we can safely use the~~s parameter or just ditch it altogether since -s seems to be the default.