More than one function was declared with the #[start] attribute.
Erroneous code example:
#![feature(start)]
#[start]
fn foo(argc: isize, argv: *const *const u8) -> isize {}
#[start]
fn f(argc: isize, argv: *const *const u8) -> isize {}
// error: multiple 'start' functions
This error indicates that the compiler found multiple functions with the
#[start] attribute. This is an error because there must be a unique entry
point into a Rust program. Example:
#![feature(start)]
#[start]
fn foo(argc: isize, argv: *const *const u8) -> isize { 0 } // ok!