PCRE2 library support. The PCRE2 library is now used by default if found, instead of the original PCRE library. If needed for some reason, this can be disabled with the --without-pcre2 configure option. To make it possible to specify paths to the library and include files via --with-cc-opt / --with-ld-opt, the library is first tested without any additional paths and options. If this fails, the pcre2-config script is used. Similarly to the original PCRE library, it is now possible to build PCRE2 from sources with nginx configure, by using the --with-pcre= option. It automatically detects if PCRE or PCRE2 sources are provided. Note that compiling PCRE2 10.33 and later requires inttypes.h. When compiling on Windows with MSVC, inttypes.h is only available starting with MSVC 2013. In older versions some replacement needs to be provided ("echo '#include <stdint.h>' > pcre2-10.xx/src/inttypes.h" is good enough for MSVC 2010). The interface on nginx side remains unchanged.