Preliminary work on jdk build time improvements

[Brad Wetmore]

This is a great optimization.

A couple comments.

Platform.gmk:

Haven't quite figured out why if MAKELEVEL=0 you export $1:=$2, but only 
export $1 if MAKELEVEL != 0.  Sure there's a good reason why, doc'ing it 
would be appreciated.

48/49:  (if $(strip $1)...

according to the gnumake docs:

     $(if condition,then-part[,else-part])

     The first argument, condition, first has all preceding and trailing
     whitespace stripped, then is expanded...

I don't think you need to specifically strip.

I like the $(or...) mods.  Cleans up the logic very nicely.

Defs-windows.gmk

Not sure why you added 2 spaces of indention on lines 85-87.

Brad


Kelly O'Hair wrote:
> 
> Here is a preliminary (and incomplete) webrev on some changes
> I've been working on to reduce the build time.
> 
> 6875240: Reduce Makefile build time by limiting repeated exec's (mostly 
> for cygwin building)
> 
> http://cr.openjdk.java.net/~ohair/openjdk7/jdk7-build-cygwin/webrev/
> 
> The Windows cygwin builds will benefit the most on this, but
> all platforms will get some benefits.
> 
> Comments and suggestions on this are welcome.
> 
> -kto