diff --git a/CMakeLists.txt b/CMakeLists.txt
index 81d3ce14..0323be13 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -486,6 +486,8 @@ CHECK_TYPE_SIZE("void *" EVENT__SIZEOF_VOID_P)
 #CHECK_FILE_OFFSET_BITS()
 #set(EVENT___FILE_OFFSET_BITS _FILE_OFFSET_BITS)
 
+include(CheckWaitpidSupportWNOWAIT)
+
 # Verify kqueue works with pipes.
 if (EVENT__HAVE_KQUEUE)
     if (CMAKE_CROSSCOMPILING AND NOT EVENT__FORCE_KQUEUE_CHECK)
diff --git a/cmake/CheckWaitpidSupportWNOWAIT.cmake b/cmake/CheckWaitpidSupportWNOWAIT.cmake
new file mode 100644
index 00000000..1a73db37
--- /dev/null
+++ b/cmake/CheckWaitpidSupportWNOWAIT.cmake
@@ -0,0 +1,18 @@
+include(CheckCSourceRuns)
+
+check_c_source_runs(
+"
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdlib.h>
+
+int
+main(int argc, char** argv)
+{
+    pid_t pid;
+    int status;
+    if ((pid = fork()) == 0) _exit(0);
+    _exit(waitpid(pid, &status, WNOWAIT) == -1);
+}"
+EVENT__HAVE_WAITPID_WITH_WNOWAIT)
diff --git a/configure.ac b/configure.ac
index 315d97a5..0c41de65 100644
--- a/configure.ac
+++ b/configure.ac
@@ -605,6 +605,26 @@ main(int argc, char **argv)
 fi
 AM_CONDITIONAL(EPOLL_BACKEND, [test "x$haveepoll" = "xyes"])
 
+AC_MSG_CHECKING(waitpid support WNOWAIT)
+AC_TRY_RUN(
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdlib.h>
+
+int
+main(int argc, char** argv)
+{
+    pid_t pid;
+    int status;
+    if ((pid = fork()) == 0) _exit(0);
+    _exit(waitpid(pid, &status, WNOWAIT) == -1);
+}, [AC_MSG_RESULT(yes)
+AC_DEFINE(HAVE_WAITPID_WITH_WNOWAIT, 1,
+[Define if waitpid() supports WNOWAIT])
+], AC_MSG_RESULT(no), AC_MSG_RESULT(no))
+
+
 haveeventports=no
 AC_CHECK_FUNCS(port_create, [haveeventports=yes], )
 if test "x$haveeventports" = "xyes" ; then
diff --git a/event-config.h.cmake b/event-config.h.cmake
index b47a7c4c..6a322a69 100644
--- a/event-config.h.cmake
+++ b/event-config.h.cmake
@@ -535,4 +535,7 @@
 /* Define to 1 if you have ERR_remove_thread_stat(). */
 #cmakedefine EVENT__HAVE_ERR_REMOVE_THREAD_STATE
 
+/* Define if waitpid() supports WNOWAIT */
+#cmakedefine EVENT__HAVE_WAITPID_WITH_WNOWAIT
+
 #endif
diff --git a/test/regress.c b/test/regress.c
index 8879d161..6b6ca9f4 100644
--- a/test/regress.c
+++ b/test/regress.c
@@ -855,6 +855,11 @@ test_fork(void)
 	int status;
 	struct event ev, sig_ev, usr_ev, existing_ev;
 	pid_t pid;
+	int wait_flags = 0;
+
+#ifdef EVENT__HAVE_WAITPID_WITH_WNOWAIT
+	wait_flags |= WNOWAIT;
+#endif
 
 	setup_test("After fork: ");
 
@@ -929,8 +934,8 @@ test_fork(void)
 	}
 
 	TT_BLATHER(("Before waitpid"));
-	if (waitpid(pid, &status, 0) == -1) {
-		fprintf(stdout, "FAILED (fork)\n");
+	if (waitpid(pid, &status, wait_flags) == -1) {
+		perror("waitpid");
 		exit(1);
 	}
 	TT_BLATHER(("After waitpid"));