‘is’ may be used uninitialized [-Werror=maybe-uninitialized]

[Lassebq]

[  0%] Building C object lib/CMakeFiles/websockets.dir/roles/http/server/server.c.o
/home/lassebq/Stuff/git/arrpc-c/libwebsockets/lib/roles/http/server/server.c: In function ‘_lws_vhost_init_server_af’:
/home/lassebq/Stuff/git/arrpc-c/libwebsockets/lib/roles/http/server/server.c:337:47: error: ‘is’ may be used uninitialized [-Werror=maybe-uninitialized]
  337 |                         a->vhost->listen_port = is;
      |                         ~~~~~~~~~~~~~~~~~~~~~~^~~~
/home/lassebq/Stuff/git/arrpc-c/libwebsockets/lib/roles/http/server/server.c:96:20: note: ‘is’ was declared here
   96 |         int m = 0, is;
      |                    ^~
cc1: all warnings being treated as errors
make[3]: *** [lib/CMakeFiles/websockets.dir/build.make:1294: lib/CMakeFiles/websockets.dir/roles/http/server/server.c.o] Error 1
make[2]: *** [CMakeFiles/Makefile2:3924: lib/CMakeFiles/websockets.dir/all] Error 2
make[1]: *** [Makefile:166: all] Error 2
make[1]: Leaving directory '/media/Stuff/git/arrpc-c/libwebsockets/build'
make: *** [Makefile:3: lws] Error 2

lws:
	mkdir -p libwebsockets/build
	cd libwebsockets/build && cmake -DCMAKE_BUILD_TYPE=Release .. && make

gcc (GCC) 13.2.1 20230801
Copyright (C) 2023 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[Lassebq]

Seems to work when building manually, makefile from my project doesn't work for some reason

[lws-team]

Not sure the warning is not a false positive in practice. But I can also see there's room for it to get confused, I pushed a small patch on main zeroing is.

[Lassebq]

lws:
	mkdir -p libwebsockets/build
	cd libwebsockets/build
	cmake -B libwebsockets/build -S libwebsockets
	make -C libwebsockets/build

This makefile works. I don't know what was happening with a one-liner

[Lassebq]

-DCMAKE_BUILD_TYPE=Release was the issue it seems.