# ------------------------------------------------------------------------------
-AC_SEARCH_LIBS([mq_open], [rt], [], [AC_MSG_ERROR([*** POSIX RT library not found])])
AC_SEARCH_LIBS([dlsym], [dl], [], [AC_MSG_ERROR([*** Dynamic linking loader library not found])])
+AC_CHECK_HEADERS([sys/capability.h], [], [AC_MSG_ERROR([*** POSIX caps headers not found])])
+
+# unconditionally pull-in librt with old glibc versions
+AC_SEARCH_LIBS([clock_gettime], [rt], [], [])
save_LIBS="$LIBS"
LIBS=
AC_SEARCH_LIBS([cap_init], [cap], [], [AC_MSG_ERROR([*** POSIX caps library not found])])
-AC_CHECK_HEADERS([sys/capability.h], [], [AC_MSG_ERROR([*** POSIX caps headers not found])])
CAP_LIBS="$LIBS"
-LIBS="$save_LIBS"
AC_SUBST(CAP_LIBS)
+LIBS=
+AC_SEARCH_LIBS([mq_open], [rt], [], [AC_MSG_ERROR([*** POSIX RT library not found])])
+RT_LIBS="$LIBS"
+AC_SUBST(RT_LIBS)
+LIBS="$save_LIBS"
+
AC_CHECK_FUNCS([fanotify_init fanotify_mark])
AC_CHECK_FUNCS([__secure_getenv secure_getenv])
AC_CHECK_DECLS([gettid, pivot_root, name_to_handle_at], [], [], [[#include <sys/types.h>