libvpx: Pull from upstream

source/libvpx/docs.mk

 ##
 ##  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 ##
 ##  Use of this source code is governed by a BSD-style license
 ##  that can be found in the LICENSE file in the root of the source
 ##  tree. An additional intellectual property rights grant can be found
 ##  in the file PATENTS.  All contributing project authors may
 ##  be found in the AUTHORS file in the root of the source tree.
 ##
 
@@ skipping 12 matching lines @@
 # Other doxy files sourced in Markdown
 TXT_DOX = $(call enabled,TXT_DOX)
 
 %.dox: %.txt
         @echo "    [DOXY] $@"
         @$(SRC_PATH_BARE)/examples/gen_example_doxy.php \
              $(@:.dox=)  "$($@.DESC)" > $@ < $<
 
 
 EXAMPLE_PATH += $(SRC_PATH_BARE) #for CHANGELOG, README, etc
+EXAMPLE_PATH += $(SRC_PATH_BARE)/examples
 
+doxyfile: $(if $(findstring examples, $(ALL_TARGETS)),examples.doxy)
 doxyfile: libs.doxy_template libs.doxy
         @echo "    [CREATE] $@"
         @cat $^ > $@
         @echo "STRIP_FROM_PATH += $(SRC_PATH_BARE) $(BUILD_ROOT)" >> $@
         @echo "INPUT += $(addprefix $(SRC_PATH_BARE)/,$(CODEC_DOX))" >> $@;
         @echo "INPUT += $(TXT_DOX)" >> $@;
         @echo "EXAMPLE_PATH += $(EXAMPLE_PATH)" >> $@
 
 CLEAN-OBJS += doxyfile $(wildcard docs/html/*)
 docs/html/index.html: doxyfile $(CODEC_DOX) $(TXT_DOX)
         @echo "    [DOXYGEN] $<"
         @doxygen $<
 DOCS-yes += docs/html/index.html
 
 DIST-DOCS-yes = $(wildcard docs/html/*)
 DIST-DOCS-$(CONFIG_CODEC_SRCS) += $(addprefix src/,$(CODEC_DOX))
 DIST-DOCS-$(CONFIG_CODEC_SRCS) += src/libs.doxy_template
 DIST-DOCS-yes                  += CHANGELOG
 DIST-DOCS-yes                  += README