diff --git a/configure.ac b/configure.ac
index aff1b7ca72..f54f5f8270 100644
--- a/configure.ac
+++ b/configure.ac
@@ -572,6 +572,8 @@ case $host_os in
     ;;
 esac
 
+AM_CONDITIONAL(BUILD_UNITTESTS, test x$supports_unittests = xyes)
+
 # In order to detect support of sendmmsg(), we need to escape the POSIX
 # jail by defining _GNU_SOURCE or <sys/socket.h> will not expose it.
 case $host_os in
@@ -580,15 +582,6 @@ case $host_os in
     ;;
 esac
 
-dnl Build unit tests when option --enable-debug is given.
-if test "x$want_debug" = "xyes" &&
-   test "x$supports_unittests" = "xyes"; then
-  want_unittests=yes
-else
-  want_unittests=no
-fi
-AM_CONDITIONAL(BUILD_UNITTESTS, test x$want_unittests = xyes)
-
 dnl Apply curl debug options to test servers
 OPT_SERVER_DEBUG="default"
 AC_ARG_ENABLE(server-debug,
diff --git a/lib/altsvc.c b/lib/altsvc.c
index c4dca59f3d..77bbbdb88e 100644
--- a/lib/altsvc.c
+++ b/lib/altsvc.c
@@ -438,7 +438,7 @@ static void altsvc_flush(struct altsvcinfo *asi, enum alpnid srcalpnid,
   }
 }
 
-#ifdef DEBUGBUILD
+#if defined(DEBUGBUILD) || defined(UNITTESTS)
 /* to play well with debug builds, we can *set* a fixed time this will
    return */
 static time_t altsvc_debugtime(void *unused)
diff --git a/tests/runtests.pl b/tests/runtests.pl
index ae2e5fef81..947e5b4790 100755
--- a/tests/runtests.pl
+++ b/tests/runtests.pl
@@ -804,7 +804,7 @@ sub checksystemfeatures {
     }
     close($manh);
 
-    $feature{"unittest"} = $feature{"Debug"};
+    $feature{"unittest"} = 1;
     $feature{"nghttpx"} = !!$ENV{'NGHTTPX'};
     $feature{"nghttpx-h3"} = !!$nghttpx_h3;