Function svn_stringbuf_ensure 

pub unsafe extern "C" fn svn_stringbuf_ensure(
    str_: *mut svn_stringbuf_t,
    minimum_size: apr_size_t,
)

Make sure that @a str has at least @a minimum_size bytes of space available in the memory block.

The allocated string buffer will be at least one byte larger than @a minimum_size to account for a final ‘\0’.

@note: Before Subversion 1.8 this function did not ensure space for one byte more than @a minimum_size. If compatibility with pre-1.8 behaviour is required callers must assume space for only @a minimum_size-1 data bytes plus a final ‘\0’.