Fix for bug #31254: "Max_data_length" truncated / reported wrong

(compiler issue ?)

Problem:

Improper compile-time flags on AIX prevented use of files > 2 GB. This
resulted in Max_data_length being truncated to 2 GB by MyISAM code.

Solution:

Reverted large-file changes from the fix for bug10776. We need to define
_LARGE_FILES on AIX to have support for files > 2 GB.

 Since _LARGE_FILE_API is incompatible with _LARGE_FILES and may be
automatically defined by including standards.h, we also need a
workaround to avoid this conflict.


config/ac-macros/large_file.m4:
  Reverted large-file changes from the fix for bug10776. We need to define
  _LARGE_FILES on AIX to have support for files > 2 GB.
include/my_global.h:
  _LARGE_FILE_API is defined in standards.h that is automatically included
  by at least some C++ compilers on AIX. Since it is also incompatible
  with _LARGE_FILES which is required for POSIX IO calls to be
  largefile-safe, the only workaround is to explicitely #undef
  _LARGE_FILE_API.

config/ac-macros/large_file.m4

@@ -128,8 +128,15 @@ AC_DEFUN([MYSQL_SYS_LARGEFILE],
 	  ac_cv_sys_largefile_source=1 ;;
 	esac])
 
-     # AIX 4.2 and later -- do nothing, include standards.h instead.
-     # this goes for both GNU and IBM C and C++ compilers.
+     AC_SYS_LARGEFILE_MACRO_VALUE(_LARGE_FILES,
+       ac_cv_sys_large_files,
+       [Large files support on AIX-style hosts.],
+       [case "$host_os" in
+       # Large file support on AIX is available starting from version 4.2
+       # Tested only on 5.2 and up
+       aix4.[2-9]* | aix4.1[0-9]* | aix[5-9].* | aix[1-9][0-9]*)
+         ac_cv_sys_large_files=1 ;;
+       esac])
    fi
   ])
 

include/my_global.h

@@ -100,6 +100,11 @@
 #define NETWARE_SET_SCREEN_MODE(A)
 #endif
 
+/* Workaround for _LARGE_FILES and _LARGE_FILE_API incompatibility on AIX */
+#if defined(_AIX) && defined(_LARGE_FILE_API)
+#undef _LARGE_FILE_API
+#endif
+
 /*
   The macros below are used to allow build of Universal/fat binaries of
   MySQL and MySQL applications under darwin.