+
+ dnl Persuade glibc <signal.h> to define sighandler_t.
+ AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+ AC_CHECK_TYPE([sighandler_t], [], [HAVE_SIGHANDLER_T=0], [[
+#include <signal.h>
+ ]])
+
+ dnl Check for declarations of anything we want to poison if the
+ dnl corresponding gnulib module is not in use.
+ gl_WARN_ON_USE_PREPARE([[#include <signal.h>
+ ]], [sigaction sigaddset sigdelset sigemptyset sigfillset sigismember
+ sigpending sigprocmask])