The scope of libc_nonshared.a was greatly changed in glibc 2.33 and
2.34, but only the change from 2.34 was reflected so far. Glibc 2.33
finally switched to versioned symbols for stat functions, meaning that
libc_nonshared.a no longer contains them since 2.33. Relevant files were
therefore reverted to 2.32 versions and renamed accordingly.
This commit also removes errno.c, which was probably added to
libc_nonshared.a based on a wrong assumption that glibc/include/errno.h
requires glibc/csu/errno.c. In reality errno.h should refer to
__libc_errno (not to be confused with the public __errno_location),
which should be imported from libc.so. The inclusion of errno.c resulted
in wrong compile options as well; this commit fixes them as well.
Fixes#16152
