BLT4L launcher script

Work in progress. Script must always pass shellcheck.

Basic current plan:

• Detect if we're in the Steam runtime or not (is STEAM_RUNTIME not a number?)
  • if true: set binary to libblt_loader.so
  • if false: set binary to libblt_loader_steamrt.so
• Detect if mods directory is present
  • if true: skip to #3
  • if false: copy in base folder structure from stored copy
• Detect if mods/base directory is present
  • if true: skip to #4
  • if false: copy in base lua from stored copy
• Set LD_PRELOAD and exec the game
• Detect if run without parameters (ex, just $ blt4l) and display an informative error
• Support using blt4l binaries present in the game directory rather than the system ones

others:

• perhaps a flag or something to force the Steam runtime on?
• other flags perhaps?

Current Usage

Steam launch options:

blt4l %command% [PD2 options, like -skip_intro]

Logs to $PAYDAY2/blt4l_launcher.log