inline ntp syscalls fallback

Reference:
 https://bugs.ntp.org/show_bug.cgi?id=769

Signed-off-by: James Knight <james.knight@rockwellcollins.com>
---
 configure.ac | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -1523,11 +1523,11 @@ AC_CACHE_CHECK(
     [ntp_cv_var_ntp_syscalls],
     [
 	ntp_cv_var_ntp_syscalls=no
-	case "$ac_cv_func_ntp_adjtime$ac_cv_func_ntp_gettime$ac_cv_func___adjtimex" in
+	case "$ac_cv_func_ntp_adjtime$ac_cv_func_ntp_gettime$ac_cv_func___adjtimex$ac_cv_func_adjtimex" in
 	 yesyes*)
 	    ntp_cv_var_ntp_syscalls=libc
 	    ;;
-	 *yes)
+	 *yesyes | *yesno | *noyes)
 	    ntp_cv_var_ntp_syscalls=inline
 	    ;;
 	 *)
