RFR: [9] 8043340: [macosx] Fix hard-wired paths to JavaVM.framework

[David DeHaven]

>> That will cause the -isysroot argument to be invalid. I can either make an undefined MACOSX_SDK_PATH a hard error (in configure)
> 
> Earlier failure is better.
> 
>> or I can wrap all uses of -isysroot/-iframework with ifneq blocks.
> 
> Yuck.

Agreed. I already don't like that I have to use -isysroot/-iframework, but it's what we have to live with until we're free of the JavaVM.framework dependency.

-DrD-