std: Changing the meaning of the count to splitn

This commit is an implementation of [RFC 979][rfc] which changes the meaning of
the count parameter to the `splitn` function on strings and slices. The
parameter now means the number of items that are returned from the iterator, not
the number of splits that are made.

[rfc]: https://github.com/rust-lang/rfcs/pull/979

Closes #23911
[breaking-change]

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstd/sys/unix/os.rs b/src/libstd/sys/unix/os.rs
index 7b13e951b9b..d2220bdec32 100644
--- a/src/libstd/sys/unix/os.rs
+++ b/src/libstd/sys/unix/os.rs
@@ -409,7 +409,7 @@ pub fn env() -> Env {
     };
 
     fn parse(input: &[u8]) -> (OsString, OsString) {
-        let mut it = input.splitn(1, |b| *b == b'=');
+        let mut it = input.splitn(2, |b| *b == b'=');
         let key = it.next().unwrap().to_vec();
         let default: &[u8] = &[];
         let val = it.next().unwrap_or(default).to_vec();