How to use Swift Flags inside a Run Script Build Phase in Xcode?

Should be able to use wildcards in conjunction with the $OTHER_SWIFT_FLAGS env variable.

if [[ $OTHER_SWIFT_FLAGS == *"-D MYOWNFLAG"* ]]; then
  echo "execute something (e.g. change Info.plist setting value)"
fi

You can check all available environment variables by running printenv from within a runscript phase.

The Other Swift Flags can be printed by running:

echo $OTHER_SWIFT_FLAGS

from within your runscript phase

Related