Merge the header checks in configure.ac
The build configuration contains two sets of header checks where one checks headers that are deemed essential and one checks headers that are not. The only difference being that missing essential headers display a non-fatal warning when they aren't found.
For the following reasons i think it is better to merge the sets and discard the warning.
- Commit e8cc839e41adc4975a61fee62abe7f6664fd0c0e adds
sys/capability.hto the essential header set but Tor runs fine without capabilities being available. IMO it is in the wrong set.
- Having two sets requires developers to make a choice whether headers are essential or not. Instead developers should write code that handles cases where the headers are unavailable (like the capabilities code).
- The current warning is truncated because its message is incorrectly quoted. This means the part about sending the
orconfig.hfile isn't shown and has been ineffective.