[feature] Respect PREFIX enviroment var?

[Freed-Wu]

For example, when PREFIX is set, it will use $PREFIX. if not, it will use /usr as a fallback?

[agnostic-apollo]

Support can be added in future to expand environment variables in config keys like installation_prefix or other director path keys. There are currently hard coded paths too for /data/data/com.termux/files/usr that should be replaced with a placeholder that's replaced during build time for the termux package, and it should preferably be got through the TERMUX__PREFIX env variable first if set, scoped variable design is being finalized for termux app v0.119.0 ($PREFIX will be deprecated).

• termux-create-package/src/termux-create-package

  Line 58 in 1f2f17c

  TERMUX_PREFIX = "/data/data/com.termux/files/usr"