#!/usr/bin/env bash

log () {
  echo "$@" >&2;
}

for impl in ENT_GETENTROPY_UNISTD \
            ENT_GETENTROPY_SYSRANDOM \
            ENT_GETRANDOM_SYSCALL \
            ENT_DEV_URANDOM
do
    export IMPL=$impl

    log "Trying IMPL=$IMPL"

    if IMPL=$impl make >/dev/null 2>/dev/null
    then sed -i 's|$(error IMPL must be set)|IMPL='"$impl"'|' Makefile
         log "IMPL=$IMPL works"
         exit 0
    else log "IMPL=$IMPL failed"
    fi
done

log "This shouldn't happen, something is broken."
exit 1