automake: do not emit rule with two dependents On a system using our replacement alloca, make would emit this warning: target '.deps/alloca.Po' given more than once in the same rule That arose because automake would emit a rule depending on both ./.deps/alloca.Po and .deps/alloca.Po. Normally, duplicate dependents are avoided by virtue of their names being keys in the %dep_files hash, but in this case, that particular file was specified in two different ways. * bin/automake.in (handle_ALLOCA): When the $dir prefix is empty, make it './', to ensure that when we add ./.deps/alloca.Po it is deduped. See: http://bugs/gnu/org/22702