ares_process.c uses htonl, which needs <arpa/inet.h> included.
ares_getnameinfo.c uses a dynamically selected format string for
sprintf, which -Wformat-literal doesn't like. Usually one would use
inttypes.h and a format string "%" PRIu32, but C99 is too new for some
supported platforms.
On a build where MSAN has been manually set up (which involves
using an MSAN-instrumented version of the standard C++ library, see
https://github.com/google/sanitizers/wiki/MemorySanitizerLibcxxHowTo)
there's a warning about use of uninitialized memory here. It
might be a false positive, but the fix is trivial so include it.
Add a new ares_library_init_mem() initialization function for the
library which allows the library user to specify their own malloc,
realloc & free equivalents for use library-wide.
Store these function pointers in library-wide global variables,
defaulting to libc's malloc(), realloc() and free().
Change all calls to malloc, realloc and free to use the function pointer
instead. Also ensure that ares_strdup() is always available
(even if the local environment includes strdup(3)), and change the
library code to always use it.
Convert calls to calloc() to use ares_malloc() + memset
Add comments for the benefit of the lcov tool, marking
lines that cannot be hit. Typically these are fall-back
protection arms that are already covered by earlier checks,
and so it's not worth taking out the unhittable code (in case
someone changes the code between the two places in future).
Make sure that the symbols are always exported and present in c-ares.
Make the headers prefixed with 'ares'.
Removed the inet_ntop.h version as it no longer features any content.
Upon socket address family and length validation failure return ARES_ENOTIMP
in callback again, this is the error code documented in man page and used
mostly all over the library.
Validate socket address family and that the socket address length is appropriate
for the specified family. Failure is reported with ARES_EBADFAMILY in callback.