JDK Builds on Windows

I need to add this to the JDK build documentation, but it may be helpful to have it posted here for some people.

Building the JDK on Windows can be difficult at times, so if it hasn't been mentioned before, here are a few clues:

• When using MKS, make sure that the PATH setting has the ${ROOTDIR}/mksnt and ${ROOTDIR}/bin directories BEFORE the system paths. Ideally they should be the first items in your PATH. There are conflicts between the MKS tools and what is supplied in Windows, and you don't want a mixture.
  I cannot verify or reproduce this, but there might be some kind of issue regarding long PATH values on Windows. Even with MKS in the right order in PATH, if many paths are placed before MKS, sometimes this doesn't work. So my recommendation is is to place MKS very early in PATH.
• When using CYGWIN, the same thing is true, make sure /usr/bin is before the system directories. Mixtures of tools will often not work.
• Use an MKS shell when you start the gnumake.exe (GNU make built for MKS). Starting make in a Windows cmd.exe command window will often not work.
• Use a CYGWIN shell when you start the /usr/bin/make of CYGWIN, if you don't you might get an error like:

  /bin/sh: cannot duplicate fd 31 to fd 0: Bad file descriptor

• The 3.81 version of make (in the latest CYGWIN) does not understand paths that use a drive letter like C:\ or C:/. Which means you cannot use this version of GNU make to build the JDK. It sounds like this is being fixed but it may take some time to get the latest CYGWIN fixed. You need make version 3.78.1 to 3.80, maybe 3.82 if this problem is addressed in tha version, although it sounds like it's a matter of how you build GNU make perhaps? So get an older version of the make command.
• There have been some reports of the latest find command in CYGWIN is also broken (version 4.3.2 as reported by Dmitri), perhaps with the drive letter path names too. So get an older version (Dmitri recommends 4.3.0) of the find command.
• If you are building JDK5, you may need to
  unset TMPDIR
  unset TMP
  in your environment. The JDK5 makefiles used these as make variables and they can cause conflicts with the environment variable version used by MKS. I don't know if this is also a problem with CYGWIN since JDK5 didn't build very reliably with CYGWIN anyway. In JDK6, the makefiles were changed to not use these names.
• The Windows Visual Studio compiler you are using should be in your PATH. You can't run the cl.exe compilers with a full path like C:/.../Bin/cl.exe without also having that Bin in your PATH settings. If you get an error message that says something about not being able to get CC_VERSION, then try running cl yourself in the same shell, perhaps compile and link a small hello world program to verify that works from the shell command line.
• When setting the JDK ALT_* variables in your environment use the pathname style of "C:/", not "C:\" or CYGWIN's "/cygdrive/C/". Ideally, you should also try and use the path names without spaces (see MKS dosname -s and CYGWIN cygpath -s -m). With JDK6, many ALT_* variables should not need to be set and the makefiles should figure it all out, so try using as few ALT_* variables as possible. The one exception is ALT_UNIXCOMMAND_PATH for CYGWIN, which is by default /usr/bin, but should be a CYGWIN style path if you need to set it for some bizarre reason.