We've had several recent instances where our Windows files (solr.cmd, solr.in.cmd) end up getting their Windows-specific line-endings stripped out. This causes chunks of those scripts to fail when run on Windows.
SOLR-13977 fixed an issue where bin\solr.cmd create -c failed, and the problem was fixed and recurred again within a week.
Generally, contributors/committers can prevent this by setting their core.autocrlf git setting to input. But we should also put repository-wide settings in place exempting certain files from line-ending conversion entirely.
This issue proposes adding a .gitattributes setting to special-case OS-specific files (bash scripts, Windows batch files, etc.) This will prevent solr.cmd's line endings from being changed by committers who forget to configure the setting on a new machine, etc.