prewarm-launcher.c fails to build on macOS MSG_NOSIGNAL undefined

[derekschrock]

Describe the bug No MSG_NOSIGNAL on macOS

To Reproduce Steps to reproduce the behavior:

1. Build on macOS
2. See error

Screenshots

clang -DKITTY_LIB_PATH="../Resources/kitty" -Wall -pedantic-errors -Werror -fpie -O3 -I/opt/local/Library/Frameworks/Python.framework/Versions/3.10/include/python3.10 -I /opt/local/include -c prewarm-launcher.c -o build/prewarm-launcher.o
prewarm-launcher.c:467:59: error: use of undeclared identifier 'MSG_NOSIGNAL'
    while ((n = sendmsg(socket_fd, &launch_msg_container, MSG_NOSIGNAL)) < 0 && errno == EINTR);
                                                          ^
prewarm-launcher.c:629:77: error: use of undeclared identifier 'MSG_NOSIGNAL'
    ssize_t n = safe_send(socket_fd, send_on_socket.buf, send_on_socket.sz, MSG_NOSIGNAL);

Solutions

• Like kitty/child-monitor.c:38 add #ifndef to prewarm-launcher.c or #define MSG_NOSIGNAL 0 to the #ifdef __APPLE__ block
• Move #ifndef to a .h that's shared between the two
• build time define in setup.py

[kovidgoyal]

It builds fine on macOS, kitty is built on macOS CI for every commit. What version of macOS are you building on?

[derekschrock]

10.15.7 (19H2026)

I thought something seemed odd... I thought I built kitty recently on my macOS 12 machine. Guess it has been a while since I've rebuilt kitty here.