Refactor dependency checks to use associative arrays for clearer erro…

[skorotkiewicz]

Description

Replaces the previous static list of required commands with a Bash associative array that maps each command to the package needed for its installation. This makes the script more maintainable and provides clearer error messages, indicating exactly which package should be installed when a command is missing.

Changes

• Removed the simple requirements array and the generic error message.
• Introduced declare -A pkg_for_cmd to store command‑to‑package mappings (emmake → emscripten, make → base-devel).
• Updated the loop to iterate over the associative array keys, checking each command with command -v.
• Enhanced the failure message to specify the missing command and the corresponding package to install.
• Minor formatting and comment cleanup.