openjdk: fix do_install for out of source builds

use ${B} to specify the build directory, thus keep working for
daisy and older versions as well as for dizzy and newer.
openjdk-7: enable xawt

The build of xawt has been disabled as its build seemed to fail during a qemu
call to generate a file with information on variable sizes.

This patch enables xawt and fixes the qemu run.

GENERATING .../icedtea-2.3.12/build/openjdk.build/gensrc/sun/awt/X11/generator/sizes.32
/lib/ld-linux-armhf.so.3: No such file or directory

Despite the error this generated an empty sizes.32 file. On subsequent bitbake
runs the compilation did not rerun qemu and followup errors ended the bitbake.

linking the sizer.32 binary with -static fixed this.
As a safeguard an empty sizes.32 file is now deleted to make also subsequent
builds fail at the position of the inital error.
icedtea6-native: fix native-vsyscall failing

On a Fedora 20 build machine icedtea6-native fails with:
x86_64-linux/icedtea6-native/1.8.11-r5.3/icedtea6-1.8.11/openjdk-ecj/hotspot/src/os/linux/vm/os_linux.cpp:2431:60: error: expression cannot be used as a function
    vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
                                                             ^
 make[7]: *** [os_linux.o] Error 1

The patch makes the build succeed. (On an openSUSE 13.1 machine the build succeeds with and without the patch)
Merge branch 'xawt'
Merge branch 'fedora20'