As part of the fix for BUILDTOOLS-301, commit e2243e9cfc8 was applied to Spigot and 60cf7613510 was applied to BuildTools. However, given that e2243e9cfc8 was not backported to older versions of Spigot, attempting to build Spigot fails for any minecraft revision before 1.11.2.

This issue is compounded by the fact that 60cf7613510 disrespects the SHELL environmental variable, making it impossible to build pre-1.11.2 versions with BuildTools after and including 60cf7613510 given that one can no longer instruct BuildTools to use bash.

This issue can be resolved by either:

• Backporting e2243e9cfc8 to all older revisions of minecraft.
• Reverting 60cf7613510 to allow users to set the SHELL environmental variable to bash as necessary.
• Adding special logic in BuildTools that selectively uses bash on older revisions.