warning SYS_pidfd_open is not defined. Assuming 434

warning SYS_pidfd_open is not defined. Assuming 434 I got these warnings during compilation: ``` $ make fatal: Not a git repository: '/tmp/src/earlyoom-1.9.0-1/.git' Makefile:6: Could not get version from git, setting to "(unknown version)" cc -Wall -Wextra -Wformat-security -Wconversion -DVERSION=\""(unknown version)"\" -g -fstack-protector-all -std=gnu99 -o earlyoom proc_pid.c meminfo.c kill.c msg.c globals.c main.c kill.c:64:2: warning: #warning SYS_pidfd_open is not defined. Assuming 434. [-Wcpp] #warning SYS_pidfd_open is not defined. Assuming 434. ^~~~~~~ kill.c:75:2: warning: #warning SYS_process_mrelease is not defined. Assuming 448. [-Wcpp] #warning SYS_process_mrelease is not defined. Assuming 448. ^~~~~~~ kill.c: In function ‘kill_wait’: kill.c:332:80: warning: conversion to ‘long int’ from ‘unsigned int’ may change the sign of the result [-Wsign-conversion] struct timespec req = { .tv_sec = (time_t)(poll_ms / 1000), .tv_nsec = (poll_ms % 1000) * 1000000 }; ^ main.c: In function ‘poll_loop’: main.c:547:81: warning: conversion to ‘long int’ from ‘unsigned int’ may change the sign of the result [-Wsign-conversion] struct timespec req = { .tv_sec = (time_t)(sleep_ms / 1000), .tv_nsec = (sleep_ms % 1000) * 1000000 }; ^ ``` Don't know how important they are, but last two should be simple to eliminate by explicit conversion.