build: fix GCC compilation error because of call of deprecated function `siginterrupt`

Error message:

> main_eventmon.cpp:109:17: error: ‘int siginterrupt(int, int)’ is deprecated: Use sigaction with SA_RESTART instead [-Werror=deprecated-declarations]

The migration from deprecated `siginterrupt(SIGINT, 1)` to `sigaction` is
inspired by the migration done in CPython, see
https://github.com/python/cpython/commit/f9c5e3f5f61cd380f8a17c814766fc3730b7fbdf