Prepare for glibc 2.34
SIGSTKSZ is not defined as constant since glibc 2.34: https://sourceware.org/git/?p=glibc.git;a=commit;h=6c57d320484988e87e446e2e60ce42816bf51d53
SIGSTKSZ is not defined as constant since glibc 2.34: https://sourceware.org/git/?p=glibc.git;a=commit;h=6c57d320484988e87e446e2e60ce42816bf51d53