Building on windows openjdk sources (NOT setting OPENJDK=true) fails due to use of OPENJDK macro prematurely.

File jdk/make/common/shared/Platform.gmk uses OPENJDK well before it can ever be defined when building openjdk source trees.

*** /tmp/sccs.tQairO Wed Jan 23 17:06:17 2008
--- Platform.gmk Wed Jan 23 17:03:33 2008
***************
*** 93,102 ****
  # Normal boot jdk is previous release, but a hard requirement is a 1.5 boot
  REQUIRED_BOOT_VER = 1.5
  
! #This is specific to OpenJDK build
! ifdef OPENJDK
    REQUIRED_FREETYPE_VERSION=2.3.0
- endif
  
  #
  # Prune out all known SCM (Source Code Management) directories
--- 93,100 ----
  # Normal boot jdk is previous release, but a hard requirement is a 1.5 boot
  REQUIRED_BOOT_VER = 1.5
  
! # If we are using freetype, this is the required version
  REQUIRED_FREETYPE_VERSION=2.3.0
  
  #
  # Prune out all known SCM (Source Code Management) directories