* configure.in, Makefile.common.in: add support for ccache,

* configure.in, Makefile.common.in: add support for ccache,
  remove spurious $VERSION output, detect doc-tools even without
  --enable-doc to facilitate later manual doc-builds, minor cleanup
* configure: regenerated

* doc/Makefile.in: quieten pdflatex, makeindex, and latex2html,
  avoid races in parallel VPATH builds
* doc/clean.mk: remove .lyx files in the builddir for VPATH builds
* doc/sdccman.lyx: mention --without-ccache configure option

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@5229 4a8a32a2-be11-0410-ad9d-d568d2c75423