PEGTL: avoiding mmap on Windows until we upgrade to PEGTL v3

because PEGTL v2 API doesn't support Unicode filenames
(and also, including <windows.h> has side-effects)

include/gemmi/third_party/tao/NOTES

@@ -1,8 +1,11 @@
 This directory contains files from PEGTL 2.8.3:
- LICENSE and include/tao/* except include/tao/pegtl/contrib
-with minor local modifications (in position.hpp and input_error.hpp):
+ LICENSE and include/tao/pegtl* except contrib/ and file_mapper_win32.hpp
+with minor modifications (in position.hpp, input_error.hpp, file_input.hpp):
 - changed formatting of error messages,
 - using std::system_error instead of pegtl::input_error.
+- avoiding mmap on Windows (until we upgrade to PEGTL v3),
+  because PEGTL v2 API doesn't support Unicode filenames
+  (and also, including <windows.h> has side-effects)
 
 PEGTL can be updated to v3 only when gemmi drops support for C++11/14.
 https://github.com/project-gemmi/gemmi/issues/212

include/gemmi/third_party/tao/pegtl/file_input.hpp

@@ -12,7 +12,7 @@
 #include <unistd.h>  // Required for _POSIX_MAPPED_FILES
 #endif
 
-#if defined( _POSIX_MAPPED_FILES ) || defined( _WIN32 )
+#if defined( _POSIX_MAPPED_FILES )
 #include "mmap_input.hpp"
 #else
 #include "read_input.hpp"
@@ -22,7 +22,7 @@ namespace tao
 {
    namespace TAO_PEGTL_NAMESPACE
    {
-#if defined( _POSIX_MAPPED_FILES ) || defined( _WIN32 )
+#if defined( _POSIX_MAPPED_FILES )
       template< tracking_mode P = tracking_mode::eager, typename Eol = eol::lf_crlf >
       struct file_input
          : mmap_input< P, Eol >