+POSIX recommends that when specifying SA_RESETHAND, SA_NODEFER must
+also be specified.
+
+@item
+Support for SA_ONSTACK is missing on some platforms:
+mingw, cygwin.
+
+@item
+Support for SA_SIGINFO is missing on some platforms:
+mingw, Interix 3.5.
+
+@item
+Support for SIGCHLD, and thus for SA_NOCLDSTOP and SA_NOCLDWAIT, is
+missing on some platforms:
+mingw.
+
+@item
+Support for SA_RESTART is missing on some platforms: