Leak spotted by valgrind. ok stsp@

Avoids leaking the node structure returned from add_node(). ok op@

Not everywhere getline does an implicit fflush, so we might end up not showing the prompt to the user. Spotted on alpine with muslc. ok Thomas Adams

while here drop the ternary too: if add_node succeeds `new_node' is non-NULL. ok stsp@

ok stsp@

The tailq should ideally be empty when we reach got_commit_graph_close, but consumer code may exit the commit graph loop earlier. spotted by and ok stsp@

ok jrick

ok stsp@

ok stsp@

pack_fds_tmp is not always free'd. However, while here, simplify it to not use a temporary array. ok stsp@

ok stsp@

ok stsp@

ok stsp@

commit_id is not NULL if got_repo_match_object_id returned successfully. ok stsp@

use the faster headers-only mode for diff3