RFR: JDK-8038340: Cleanup and fix sysroot and devkit handling on Linux and Solaris

[Erik Joelsson]

Hello,

(including 2d-dev/awt-dev because I'm changing linker flags on desktop 
libs.)

In preparation for upgrading compilers and build platforms, we would 
like to get better separation between the two. At least on Linux and 
Solaris this is certainly possible. Some work for this was already done 
in Jdk 8 but it was never taken all the way through into actual usage.

In this bug, the configure parameters relating to this will be changed to:

--with-sysroot: Sets a sysroot directory that will be propagated to the 
compiler (gcc --sysroot) if supported and which will be used by 
configure to look for all dependencies like headers and libraries. (old 
--with-sys-root will be kept for compatibility as an alias)

--with-toolchain-path: Prepends to the path when looking for compilers 
and other target specific tools. Replaces --with-tools-dir, which will 
also be kept for compatibility as an alias.

--with-extra-path: Prepends to the path when looking for everything.

--with-devkit: Points to the root of a devkit. A devkit may have a 
"devkit.info" in its root detailing values for the above three 
parameters. If not, the fallback behavior is what it used to do. (set 
toolchain_path to devkit/bin and some options for subdirs for sysroot)


Along with these changes some more was needed and done:

* To get it to work properly on Solaris, the OPENWIN variables were 
removed and replaced with X_LIBS and X_CFLAGS. Several unnecessary 
runtime paths for awt* libs were removed and some were added where they 
were actually needed instead. All the libs have been verified to still 
find their dependencies with ldd.

* The devkit generation makefiles for linux (in root/make/devkit) were 
updated to the proposed compiler versions and adding the devkit.info file.

* A minor fix in compare.sh that was missed in an earlier patch.

Bug: https://bugs.openjdk.java.net/browse/JDK-8038340
Webrevs:
http://cr.openjdk.java.net/~erikj/8038340/webrev.root.01/
http://cr.openjdk.java.net/~erikj/8038340/webrev.jdk.01/

/Erik