Add test and man page updates for non-iopoll uring_cmds on IORING_SETUP_IOPOLL rings

[calebsander]

As requested...

Add a test (iopoll-sync) issuing non-iopoll SOCKET_URING_OP_{GET,SET}SOCKOPT uring_cmds to an IORING_SETUP_IOPOLL io_uring.

Update various man pages to reflect the current set of opcodes supported by the kernel with IORING_SETUP_IOPOLL.

---

git request-pull output:

The following changes since commit 1e9a937e10e892595ad09faeec3e5ee79646135e:

  test/fdinfo: don't use io_uring_submit() return value for SQPOLL (2026-03-17 14:51:26 -0600)

are available in the Git repository at:

  git@calebsander-github:calebsander/liburing.git feature/mixed-iopoll

for you to fetch changes up to e20dcbba7897b14058635b343ac31dc84396b1d9:

  man: update comments about non-polled requests with IORING_SETUP_IOPOLL (2026-03-18 18:54:42 -0600)

----------------------------------------------------------------
Caleb Sander Mateos (3):
      test: test non-iopoll uring_cmds on IORING_SETUP_IOPOLL rings
      man: remove note about IORING_SETUP_IOPOLL + IORING_OP_NOP
      man: update comments about non-polled requests with IORING_SETUP_IOPOLL

 man/io_uring_enter.2       |   7 -------
 man/io_uring_setup.2       |  12 +++++++++---
 man/io_uring_setup_flags.7 |  29 +++++++++++++++++++++++++----
 test/Makefile              |   1 +
 test/iopoll-sync.c         | 129 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 164 insertions(+), 14 deletions(-)
 create mode 100644 test/iopoll-sync.c

[axboe]

Looks good outside of:

iopoll-sync.c:13:9: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   13 | int main()
      |         ^
      |          void
1 error generated.

Can you fix that one up?