[NaCl SDK] Cleanup references to old newlib toolchain

native_client_sdk/src/doc/Makefile

 # Makefile for Sphinx documentation
 #
 
 # You can set these variables from the command line.
 SPHINXOPTS    = -W
 SPHINXBUILD   = sphinx-build
 BUILDDIR      = _build
 CHROMESITE_BUILDDIR = $(realpath ../../doc_generated)
 PORT = 8000
 
@@ skipping 32 matching lines @@
         @echo
         @echo "Link check complete; look for any errors in the above output " \
               "or in $(BUILDDIR)/linkcheck/output.txt."
 
 doctest:
         $(SPHINXBUILD) -b doctest $(ALLSPHINXOPTS) $(BUILDDIR)/doctest
         @echo "Testing of doctests in the sources finished, look at the " \
               "results in $(BUILDDIR)/doctest/output.txt."
 
 chromesite:
-        -rm $(CHROMESITE_BUILDDIR)/.buildinfo
+        -rm -f $(CHROMESITE_BUILDDIR)/.buildinfo
         doxygen/generate_docs.py $(CHROMESITE_BUILDDIR)
         $(SPHINXBUILD) -b chromesite $(ALLSPHINXOPTS) $(CHROMESITE_BUILDDIR)
         rm -rf $(CHROMESITE_BUILDDIR)/images
         cp -r $(CHROMESITE_BUILDDIR)/_images $(CHROMESITE_BUILDDIR)/images
         rm -rf $(CHROMESITE_BUILDDIR)/{_images,searchindex.js}
         @echo
         @echo "Build finished. The HTML pages are in $(CHROMESITE_BUILDDIR)"
 
 chromesite_rst:
         -rm $(CHROMESITE_BUILDDIR)/.buildinfo
         $(SPHINXBUILD) -b chromesite $(ALLSPHINXOPTS) $(CHROMESITE_BUILDDIR)
         rm -rf $(CHROMESITE_BUILDDIR)/images
         cp -r $(CHROMESITE_BUILDDIR)/_images $(CHROMESITE_BUILDDIR)/images
         rm -rf $(CHROMESITE_BUILDDIR)/{_images,searchindex.js}
 
 presubmit:
         -rm $(BUILDDIR)/.buildinfo
         $(SPHINXBUILD) -b chromesite $(ALLSPHINXOPTS) $(BUILDDIR)
 
 serve: chromesite_rst
         ../../../chrome/common/extensions/docs/server2/preview.py -p $(PORT)