nginxModules.rtmp: v1.1.11 -> v1.2.0 & add support for gcc-7

[andir]

Motivation for this change

The RTMP module requires a few /* fall through */ comments with gcc-7
which are included in the introduced patch. The used patch was proposed
to the upstream repo [1] quite a while ago so it probably is best to
include it for now.

[1] arut/nginx-rtmp-module#1125

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

[andir]

CC maintainers @thoughtpolice @raskin @fpletz

[campones]

hello

just installed ubuntu 20.04 that apparently comes with gcc9 and I m stuck with the same issue.

/root/nginx-rtmp-module-master/ngx_rtmp_eval.c:160:17: error: this statement may fall through [-Werror=implicit-fallthrough=]
160 | switch (c) {
| ^~~~~~
/root/nginx-rtmp-module-master/ngx_rtmp_eval.c:170:13: note: here
170 | case ESCAPE:
| ^~~~
cc1: all warnings being treated as errors
make[1]: *** [objs/Makefile:1479: objs/addon/nginx-rtmp-module-master/ngx_rtmp_eval.o] Error 1