The diff of what Andrew Dunstan changed on my Windows Server 2012 + MinGW to get proper builds of Postgres.

build-farm.conf.diff

Administrator@AMAZONA-AK1BTP3 ~
$ diff -c -r del/build-farm-4.9/ bf/
diff -c -r del/build-farm-4.9//build-farm.conf bf//build-farm.conf
*** del/build-farm-4.9//build-farm.conf Mon Nov 12 09:47:55 2012
--- bf//build-farm.conf Thu Jan  3 20:51:07 2013
***************
*** 35,41 ****
      tar_log_cmd => undef, # default is "tar -z -cf runlogs.tgz *.log"
      # replacement must have the same effect
      # must be absolute, can be either Unix or Windows style for MSVC
!     build_root => '/path/to/buildroot',
      use_vpath => undef, # set true to do vpath builds

      # path to directory with auxiliary web script
--- 35,41 ----
      tar_log_cmd => undef, # default is "tar -z -cf runlogs.tgz *.log"
      # replacement must have the same effect
      # must be absolute, can be either Unix or Windows style for MSVC
!     build_root => '/home/Administrator/bf/root',
      use_vpath => undef, # set true to do vpath builds

      # path to directory with auxiliary web script
***************
*** 110,116 ****
          # use a dedicated cache for the build farm. this should give us
          # very high hit rates and slightly faster cache searching.

!         CCACHE_DIR => "/home/andrew/pgfarmbuild/ccache/$branch",

          ### use these settings for CYGWIN
          # CYGWIN => 'server',
--- 110,116 ----
          # use a dedicated cache for the build farm. this should give us
          # very high hit rates and slightly faster cache searching.

!         # CCACHE_DIR => "/home/andrew/pgfarmbuild/ccache/$branch",

          ### use these settings for CYGWIN
          # CYGWIN => 'server',
***************
*** 121,132 ****
          # BF_PROXY => 'http://my.proxy.server:portnum/',

          # see below for MSVC settings

      },

      # env settings to pass to configure. These settings will only be seen by
      # configure.
!     config_env =>{CC => 'ccache gcc',},

      # don't use --prefix or --with-pgport here
      # they are set up by the script
--- 121,135 ----
          # BF_PROXY => 'http://my.proxy.server:portnum/',

          # see below for MSVC settings
+       PATH => "/mingw-w64/bin:$ENV{PATH}",

      },

      # env settings to pass to configure. These settings will only be seen by
      # configure.
!     config_env =>{
!       # CC => 'ccache gcc',
!       },

      # don't use --prefix or --with-pgport here
      # they are set up by the script
***************
*** 138,152 ****

      config_opts =>[
          qw(
!           --enable-cassert
!           --enable-debug
!           --enable-nls
            --enable-integer-datetimes
!           --with-perl
!           --with-python
!           --with-tcl
!           --with-krb5 --with-includes=/usr/include/et
!           --with-openssl
            )
      ],

--- 141,149 ----

      config_opts =>[
          qw(
!         --host=x86_64-w64-mingw32
            --enable-integer-datetimes
!           --without-zlib
            )
      ],

***************
*** 285,292 ****

      # msvc can set it up separately - see above

!     push(@{$conf{config_opts}},"--with-ldap")
!       unless $conf{using_msvc};
  }

  # libxml/libxslt support as of 8.3
--- 282,289 ----

      # msvc can set it up separately - see above

! #    push(@{$conf{config_opts}},"--with-ldap")
! #      unless $conf{using_msvc};
  }

  # libxml/libxslt support as of 8.3
***************
*** 295,302 ****

      # msvc can set it up separately - see above

!     push(@{$conf{config_opts}},"--with-libxml", "--with-libxslt")
!       unless $conf{using_msvc};
  }

  if ($branch eq 'HEAD')
--- 292,299 ----

      # msvc can set it up separately - see above

! #    push(@{$conf{config_opts}},"--with-libxml", "--with-libxslt")
!       # unless $conf{using_msvc};
  }

  if ($branch eq 'HEAD')
Only in bf/: root