The xmlrpc library is a forked, modified and bundled into the PHP source
code. Instead of having a separate *nix build system files in the xmlrpc
library this patch removes unneeded build checks.

- AC_PROG_CC is not needed to be called by the extension itself since it
  is already part of the main configure.ac and the phpize's
  configure.ac.
- UNDEF_THREADS_HACK is not used in the current codebase.
- Symbols defined by XMLRPC_HEADER_CHECKS are not used in the current
  code.
- Symbols defined by XMLRPC_FUNCTION_CHECKS are not used in the current
  code.
- AC_PROG_RANLIB is already done by the TSRM's files and isn't needed
  for the xmlrpc extension to work.
- AC_PROG_LN_S is already done by the PHP main configure.ac and also
  isn't needed by the xmlrpc extension to be built.

- AC_CHECK_SIZEOF is now called mostly only in PHP_CHECK_STDINT_TYPES()
  macro except for some parts checking for the 32 or 64 bit architecture.
- SIZEOF_CHAR removed since it is always 1
- ZEND_BIN_ID is now of a more logical pattern `BIN_48888` on 64bit
  architectures and `BIN_44444` on 32bit instead of literal string
  `BIN_SIZEOF_CHAR48888` on 64bit and `BIN_SIZEOF_CHAR44444` on 32bit.
  The unneeded SIZEOF_CHAR part has been removed.
- XMLRPC_TYPE_CHECKS removed
- The `long long int` is the same as `long long` and redundant checks
  removed accordingly.
- Removed PHP_CHECK_64BIT macro. Checking if current platform is 64bit
  or not can be also done simply by using a check of the long type on
  place. This removes redundant m4 macro PHP_CHECK_64BIT.

Changes:
- AC_TYPE_SIZE_T called on only one place (configure.ac)
- AC_FUNC_ALLOCA called on only one place (configure.ac)
- AC_TYPE_UID_T called on only one place (configure.ac)
- HAVE_STRSTR removed since strstr is part of C89 standard [1]
- Remove checks for strtol and strpbrk
- Checking for the presence of perror function is not needed anymore
  since it is part of C89 standard and PHP calls it unconditionally.
- Checking for functions strdup, setenv, strerror, and memmove done only
  on one place (configure.ac)
- outdated check for snprintf removed

1: https://port70.net/~nsz/c/c89/c89-draft.html

Autoconf 2.59d (released in 2006) [1] started promoting several macros
as not relevant for newer systems anymore, including the `AC_HEADER_STDC`.

This macro checks if given system has C89 compliant header files such
as `<string.h>`, `<stdlib.h>`, `<stdarg.h>`, `<float.h>`,... and defines
the `STDC_HEADERS` symbol [2]. Case is that current systems should be
well supported with at least C89 standard headers [3].

Given headers are still additionally checked with the `AC_PROG_CC`
macro, yet not needed anyway.

Additionally, the HAVE_MEMCPY check has been removed. The memcpy
function is standardized by C89 and later.

Refs:
[1] http://git.savannah.gnu.org/cgit/autoconf.git/tree/NEWS
[2] https://www.gnu.org/software/autoconf/manual/autoconf-2.69/autoconf.html
[3] https://port70.net/~nsz/c/c89/c89-draft.html#4.1.2

* PHP-7.3:
  Fix #77367: Negative size parameter in mb_split
  Fix #77369 - memcpy with negative length via crafted DNS response
  Fix more issues with encodilng length
  Fix #77270: imagecolormatch Out Of Bounds Write on Heap
  Fix bug #77380  (Global out of bounds read in xmlrpc base64 code)
  Fix bug #77371 (heap buffer overflow in mb regex functions - compile_string_node)
  Fix bug #77370 - check that we do not read past buffer end when parsing multibytes
  Fix #77269: Potential unsigned underflow in gdImageScale
  Fix bug #77247 (heap buffer overflow in phar_detect_phar_fname_ext)
  Fix bug #77242 (heap out of bounds read in xmlrpc_decode())
  Regenerate certs for openssl tests

* PHP-7.2:
  Fix #77369 - memcpy with negative length via crafted DNS response
  Fix more issues with encodilng length
  Fix #77270: imagecolormatch Out Of Bounds Write on Heap
  Fix bug #77380  (Global out of bounds read in xmlrpc base64 code)
  Fix bug #77371 (heap buffer overflow in mb regex functions - compile_string_node)
  Fix bug #77370 - check that we do not read past buffer end when parsing multibytes
  Fix #77269: Potential unsigned underflow in gdImageScale
  Fix bug #77247 (heap buffer overflow in phar_detect_phar_fname_ext)
  Fix bug #77242 (heap out of bounds read in xmlrpc_decode())
  Regenerate certs for openssl tests

* PHP-7.1:
  Fix #77369 - memcpy with negative length via crafted DNS response
  Fix more issues with encodilng length
  Fix #77270: imagecolormatch Out Of Bounds Write on Heap
  Fix bug #77380  (Global out of bounds read in xmlrpc base64 code)
  Fix bug #77371 (heap buffer overflow in mb regex functions - compile_string_node)
  Fix bug #77370 - check that we do not read past buffer end when parsing multibytes
  Fix #77269: Potential unsigned underflow in gdImageScale
  Fix bug #77247 (heap buffer overflow in phar_detect_phar_fname_ext)
  Fix bug #77242 (heap out of bounds read in xmlrpc_decode())
  Regenerate certs for openssl tests