In a build environment /dev/ptmx is not always present.
Bypass build time check as /dev/ptmx is alsways present at runtime.
---
 ConfigureChecks.cmake |    8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

--- a/ConfigureChecks.cmake
+++ b/ConfigureChecks.cmake
@@ -202,13 +202,7 @@ if (UNIX)
     set(HAVE_OPENPTY)
 
     EXECUTE_PROCESS(
-      COMMAND sh -c "
-        for ptm in ptc ptmx ptm ptym/clone; do
-          if test -c /dev/$ptm; then
-            echo /dev/$ptm
-            break
-          fi
-        done"
+      COMMAND sh -c "echo /dev/ptmx"
       OUTPUT_VARIABLE PTM_DEVICE
       OUTPUT_STRIP_TRAILING_WHITESPACE)
     message(STATUS "PTY multiplexer: ${PTM_DEVICE}")