Makefile.am: no recursive makefiles

Recursive Makefiles are inefficient and error prone (no proper way to
declare dependencies).  Since there's no disadvantage in having one
single Makefile, let's do it.

doc/Makefile.am

@@ -1,28 +0,0 @@
-DOCBOOK_FILES = protocol.xml
-DOCBOOK_HTML = $(patsubst %.xml,%/index.html,$(DOCBOOK_FILES))
-
-man_MANS = mpd.1 mpd.conf.5
-doc_DATA = mpdconf.example
-EXTRA_DIST = $(man_MANS) $(DOCBOOK_FILES) mpdconf.example
-
-if ENABLE_DOCUMENTATION
-protocoldir = $(docdir)/protocol
-protocol_DATA = $(wildcard protocol/*.html)
-
-$(DOCBOOK_HTML): %/index.html: %.xml
-	$(XMLTO) -o protocol --stringparam chunker.output.encoding=utf-8 html $<
-
-api/html/index.html: doxygen.conf
-	$(DOXYGEN) $<
-
-all-local: $(DOCBOOK_HTML) api/html/index.html
-
-clean-local:
-	rm -rf $(patsubst %.xml,%,$(DOCBOOK_FILES))
-	rm -rf api
-
-install-data-local: api/html/index.html
-	$(mkinstalldirs) $(DESTDIR)$(docdir)/api/html
-	$(INSTALL_DATA) -c -m 644 api/html/*.html api/html/*.css api/html/*.png api/html/*.gif $(DESTDIR)$(docdir)/api/html
-
-endif

doc/doxygen.conf

@@ -38,7 +38,7 @@ PROJECT_NUMBER         =
 # If a relative path is entered, it will be relative to the location
 # where doxygen was started. If left blank the current directory will be used.
 
-OUTPUT_DIRECTORY       = api
+OUTPUT_DIRECTORY       = doc/api
 
 # 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
@@ -534,7 +534,7 @@ WARN_LOGFILE           =
 # directories like "/usr/src/myproject". Separate the files or directories
 # with spaces.
 
-INPUT                  = ../src
+INPUT                  = src
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding, which is