handle zero-size allocations correctly

The `malloc` family of functions may return a null pointer for a
zero-size allocation, which should not be interpreted as an
out-of-memory error.

If the implementation does not return a null pointer, then handling
this will result in memory savings for zero-size types.

This also switches some code to `malloc_raw` in order to maintain a
centralized point for handling out-of-memory in `rt::global_heap`.

Closes #11634

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstd/libc.rs b/src/libstd/libc.rs
index 9cf94e5a1b8..77ac226a7f1 100644
--- a/src/libstd/libc.rs
+++ b/src/libstd/libc.rs
@@ -3223,7 +3223,7 @@ pub mod funcs {
                 pub fn strtoul(s: *c_char, endp: **c_char, base: c_int)
                                -> c_ulong;
                 pub fn calloc(nobj: size_t, size: size_t) -> *c_void;
-                pub fn malloc(size: size_t) -> *c_void;
+                pub fn malloc(size: size_t) -> *mut c_void;
                 pub fn realloc(p: *mut c_void, size: size_t) -> *mut c_void;
                 pub fn free(p: *c_void);
                 pub fn exit(status: c_int) -> !;