Tree:

46b51dce0e89acc9d3a5a729357263c4778d089e

Message:

configure.ac: expand the check for sys/tree.h do not just see if it's there, make sure it is usable. Currently, alpine sys/tree.h generates code that doesn't work with both gcc and clang (for different reasons!) so make sure we can actually use it, or fall back on the bundled version.