gh-85277: Fix building without stropts.h or empty stropts.h (#143521)

Author: shadchin

Misc/NEWS.d/next/Build/2026-01-08-22-27-07.gh-issue-85277.TotySi.rst

@@ -0,0 +1 @@
+Fix building without ``stropts.h`` or empty ``stropts.h``

Modules/posixmodule.c

@@ -9397,13 +9397,13 @@ os_openpty_impl(PyObject *module)
     if (_Py_set_inheritable(master_fd, 0, NULL) < 0)
         goto posix_error;
 
-#if !defined(__CYGWIN__) && !defined(__ANDROID__) && !defined(HAVE_DEV_PTC)
+#if defined(HAVE_STROPTS_H) && !defined(HAVE_DEV_PTC)
     ioctl(slave_fd, I_PUSH, "ptem"); /* push ptem */
     ioctl(slave_fd, I_PUSH, "ldterm"); /* push ldterm */
 #ifndef __hpux
     ioctl(slave_fd, I_PUSH, "ttcompat"); /* push ttcompat */
 #endif /* __hpux */
-#endif /* HAVE_CYGWIN */
+#endif /* defined(HAVE_STROPTS_H) && !defined(HAVE_DEV_PTC) */
 #endif /* HAVE_OPENPTY */
 
     return Py_BuildValue("(ii)", master_fd, slave_fd);

configure

@@ -3011,7 +3011,7 @@ AC_CHECK_HEADERS([ \
   io.h langinfo.h libintl.h libutil.h linux/auxvec.h sys/auxv.h linux/fs.h linux/limits.h linux/memfd.h \
   linux/netfilter_ipv4.h linux/random.h linux/soundcard.h linux/sched.h \
   linux/tipc.h linux/wait.h netdb.h net/ethernet.h netinet/in.h netpacket/packet.h poll.h process.h pthread.h pty.h \
-  sched.h setjmp.h shadow.h signal.h spawn.h stropts.h sys/audioio.h sys/bsdtty.h sys/devpoll.h \
+  sched.h setjmp.h shadow.h signal.h spawn.h sys/audioio.h sys/bsdtty.h sys/devpoll.h \
   sys/endian.h sys/epoll.h sys/event.h sys/eventfd.h sys/file.h sys/ioctl.h sys/kern_control.h \
   sys/loadavg.h sys/lock.h sys/memfd.h sys/mkdev.h sys/mman.h sys/modem.h sys/param.h sys/pidfd.h sys/poll.h \
   sys/random.h sys/resource.h sys/select.h sys/sendfile.h sys/socket.h sys/soundcard.h sys/stat.h \
@@ -3022,6 +3022,16 @@ AC_CHECK_HEADERS([ \
 AC_HEADER_DIRENT
 AC_HEADER_MAJOR
 
+# On Linux, stropts.h may be empty
+AC_CHECK_DECL([I_PUSH], [
+  AC_DEFINE([HAVE_STROPTS_H], [1],
+    [Define to 1 if you have the <stropts.h> header file.])], [], [
+    #ifdef HAVE_SYS_TYPES_H
+    #  include <sys/types.h>
+    #endif
+    #include <stropts.h>
+])
+
 # bluetooth/bluetooth.h has been known to not compile with -std=c99.
 # http://permalink.gmane.org/gmane.linux.bluez.kernel/22294
 SAVE_CFLAGS=$CFLAGS