auto merge of #8296 : erickt/rust/remove-str-trailing-nulls, r=erickt

This PR fixes #7235 and #3371, which removes trailing nulls from `str` types. Instead, it replaces the creation of c strings with a new type, `std::c_str::CString`, which wraps a malloced byte array, and respects:

*  No interior nulls
* Ends with a trailing null

1 files changed, 2 insertions, 3 deletions

diff --git a/src/rt/rust_builtin.cpp b/src/rt/rust_builtin.cpp
index 0729cc1958b..ddd452deef2 100644
--- a/src/rt/rust_builtin.cpp
+++ b/src/rt/rust_builtin.cpp
@@ -292,10 +292,9 @@ void tm_to_rust_tm(tm* in_tm, rust_tm* out_tm, int32_t gmtoff,
 
     if (zone != NULL) {
         size_t size = strlen(zone);
-        reserve_vec_exact(&out_tm->tm_zone, size + 1);
+        reserve_vec_exact(&out_tm->tm_zone, size);
         memcpy(out_tm->tm_zone->data, zone, size);
-        out_tm->tm_zone->fill = size + 1;
-        out_tm->tm_zone->data[size] = '\0';
+        out_tm->tm_zone->fill = size;
     }
 }