Add doxygen to standard build flow, if found

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

doc/.gitignore

@@ -1 +1,2 @@
 html/*
+libuev.tag

doc/Doxyfile

@@ -58,7 +58,7 @@ PROJECT_LOGO           =
 # entered, it will be relative to the location where doxygen was started. If
 # left blank the current directory will be used.
 
-OUTPUT_DIRECTORY       = doc/
+OUTPUT_DIRECTORY       = ./
 
 # If the CREATE_SUBDIRS tag is set to YES then doxygen will create 4096 sub-
 # directories (in 2 levels) under the output directory of each output format and
@@ -829,7 +829,7 @@ WARN_LOGFILE           =
 # spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = src/ src/ README.md API.md
+INPUT                  = ../src/ ../README.md API.md
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses
@@ -917,7 +917,7 @@ RECURSIVE              = NO
 # Note that relative paths are relative to the directory from which doxygen is
 # run.
 
-EXCLUDE                = src/bench.c src/private.h src/README.md
+EXCLUDE                = ../src/bench.c ../src/private.h ../src/README.md
 
 # The EXCLUDE_SYMLINKS tag can be used to select whether or not files or
 # directories that are symbolic links (a Unix file system feature) are excluded
@@ -1663,7 +1663,7 @@ MATHJAX_CODEFILE       =
 # The default value is: YES.
 # This tag requires that the tag GENERATE_HTML is set to YES.
 
-SEARCHENGINE           = YES
+SEARCHENGINE           = NO
 
 # When the SERVER_BASED_SEARCH tag is enabled the search engine will be
 # implemented using a web server instead of a web client using JavaScript. There

doc/Makefile.am

@@ -1,2 +1,21 @@
 dist_doc_DATA = API.md
 EXTRA_DIST    = Doxyfile
+
+if ENABLE_HTML
+pkghtmldir     = $(docdir)/html
+pkghtml_DATA   = html/*
+
+#
+# Doxygen rules from m4/ax_prog_doxygen.m4
+#
+@DX_RULES@
+
+$(pkghtml_DATA): doxygen-doc
+
+all-local: doc
+
+clean-local:
+	-rm -rf html
+
+doc:  doxygen-doc
+endif