Apple - Disable Command-M to minimize window

You can disable it by editing ~/Library/Preferences/.GlobalPreferences.plist:

defaults write -g NSUserKeyEquivalents -dict-add 'Minimize' '\0'

To apply the changes you have to reopen applications. If the shortcut was assigned to nil, pressing L would trigger it in Audacity.

You can "override" the default Command-M shortcut by mapping it to something else. To remap the key combination, launch System Preferences and choose Keyboard. Then the Keyboard Preferences Panel appears, click on the right tab named "Keyboard Shortcuts". You will notice many default keyboard shortcuts that you can override.

I've tried remapping Command-M using this method and it works.