Fix ar usage in Makefile for macOS compatibility

5 jobs for samuela-master-patch-09777 in 7 minutes and 19 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #24193
build:linux

00:07:19

failed #24194
build:redox

00:07:12

 
  Test
skipped #24197
allowed to fail
fmt
skipped #24195
test:linux
skipped #24196
test:redox
 
Name Stage Failure
failed
build:redox Build
src/header/sys_wait
src/header/termios
src/header/time
src/header/unistd
src/header/utime
src/header/wchar
mv "target/x86_64-unknown-redox"/include.partial "target/x86_64-unknown-redox"/include
touch "target/x86_64-unknown-redox"/include
ERROR: Job failed: exit code 1