Previously they were only guarded by `#ifndef _ANSI_SOURCE'. They are
neither ANSI nor POSIX nor std and should never have been declared here.
Declare functions like abs() as having attribute `__pure2'. Declaring them
as having type `__pure' has been a no-op for some time.
Delete obsolete comment about stub locale functions.
Use consistent formatting for the rand48 functions. These and about 30
other functions should never have been declared here either.
