guile: touch compiled modules on sstate install

guile: touch compiled modules on sstate install

When guile is installed from sstate, if the compiled files get a modified time
older than the source files then guile will produce warnings like this:

;;; note: source file /data/poky-master/tmp/sysroots/x86_64-linux/usr/share/guile/2.0/ice-9/boot-9.scm
;;; newer than compiled /data/poky-master/tmp/sysroots/x86_64-linux/usr/lib/guile/2.0/ccache/ice-9/boot-9.go

Not staging the files and letting guile re-compile them on demand won't work:

;;; compiling /data/poky-master/tmp/sysroots/x86_64-linux/usr/share/guile/2.0/system/base/compile.scm
;;; it seems /data/poky-master/tmp/sysroots/x86_64-linux/usr/share/guile/2.0/system/base/compile.scm
;;; is part of the compiler; skipping auto-compilation

So, use a sstate postinst function to explicitly touch the compiled files after
the extraction to ensure that they are fresher.

[ YOCTO #3370 ]

(From OE-Core rev: cb8fbc332f730cbb4d9c9866ee7b95d62245d121)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>