patch 8.0.0045
Problem:    Calling job_stop() right after job_start() does not work.
Solution:   Block signals while fork is still busy. (Ozaki Kiichi, closes
            #1155)
diff --git a/src/config.h.in b/src/config.h.in
index 9d35e48..62427e2 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -190,6 +190,7 @@
 #undef HAVE_SIGSET
 #undef HAVE_SIGSETJMP
 #undef HAVE_SIGSTACK
+#undef HAVE_SIGPROCMASK
 #undef HAVE_SIGVEC
 #undef HAVE_SMACK
 #undef HAVE_STRCASECMP