Integrate Doxygen better in the build system

This change:

 - Adds a check for the doxygen program to configure.
 - Moves the Doxyfile from src/Doxyfile to doc/Doxyfile.in.
 - Generates a doc/Doxyfile from doc/Doxyfile.in inserting
   an absolute path to the source directory, so that it
   also works when builddir != srcdir.
 - Adds `make api` rule for running doxygen; it depends on
   api/doxygen file which is never created to force the rule
   to always run.

Makefile.config.in

@@ -56,6 +56,7 @@ CATALOGS = @CATALOGS@
 CC = @CC@
 CG_COMMIT_ID = @CG_COMMIT_ID@
 CONFDIR = @CONFDIR@
+DOXYGEN = @DOXYGEN@
 GLIBC21 = @GLIBC21@
 GMOFILES = @GMOFILES@
 GMSGFMT = @GMSGFMT@
@@ -99,6 +100,7 @@ CONFIG_NLS = @CONFIG_NLS@
 CONFIG_256_COLORS = @CONFIG_256_COLORS@
 CONFIG_88_COLORS = @CONFIG_88_COLORS@
 CONFIG_ASCIIDOC = @CONFIG_ASCIIDOC@
+CONFIG_DOXYGEN = @CONFIG_DOXYGEN@
 CONFIG_BACKTRACE = @CONFIG_BACKTRACE@
 CONFIG_BITTORRENT = @CONFIG_BITTORRENT@
 CONFIG_BOOKMARKS = @CONFIG_BOOKMARKS@

configure.in

@@ -95,10 +95,18 @@ if test "x$CONFIG_DOC" != xno; then
       	if test "x$POD2HTML" != "x"; then
 		EL_CONFIG(CONFIG_POD2HTML, [Pod2HTML])
 	fi
+
+	AC_PATH_PROGS(DOXYGEN, "doxygen")
+	if test "x$DOXYGEN" != "x"; then
+		EL_CONFIG(CONFIG_DOXYGEN, [Doxygen])
+		api_srcdir="$(cd "$srcdir" && pwd)/src"
+		AC_SUBST(api_srcdir)
+	fi
 fi
 
 AC_SUBST(ASCIIDOC_FLAGS)
 AC_SUBST(CONFIG_ASCIIDOC)
+AC_SUBST(CONFIG_DOXYGEN)
 AC_SUBST(CONFIG_POD2HTML)
 AC_SUBST(CONFIG_XMLTO)
 AC_SUBST(CONFIG_JW)
@@ -106,6 +114,7 @@ AC_SUBST(CONFIG_JW)
 EL_CONFIG_DEPENDS(CONFIG_DOC, [CONFIG_ASCIIDOC CONFIG_XMLTO CONFIG_JW CONFIG_POD2HTML], [Documentation Tools])
 EL_CONFIG_DEPENDS(CONFIG_MANUAL, [MANUAL_ASCIIDOC MANUAL_XMLTO MANUAL_JW], [Manual Formats])
 EL_CONFIG_DEPENDS(CONFIG_MANPAGE, [MAN_ASCIIDOC MAN_XMLTO], [Man Page Formats])
+EL_CONFIG_DEPENDS(CONFIG_APIDOCS, [CONFIG_DOXYGEN], [API Documentation])
 
 dnl gcc specific options (to be continued at the bottom of configure)
 if test "x$ac_cv_c_compiler_gnu" = "xyes"; then
@@ -1451,6 +1460,7 @@ AC_CONFIG_FILES([ \
  contrib/elinks.spec \
  contrib/lua/hooks.lua \
  contrib/conv/w3m2links.awk \
+ doc/Doxyfile \
  doc/man/man1/elinks.1 \
  src/intl/gettext/ref-add.sed \
  src/intl/gettext/ref-del.sed

doc/.gitignore

@@ -12,3 +12,4 @@ keymap-defaults.txt
 manual.html-chunked
 option-command.txt
 option-config.txt
+Doxyfile

doc/Doxyfile.in

@@ -7,7 +7,7 @@
 DOXYFILE_ENCODING      = UTF-8
 PROJECT_NAME           = ELinks
 PROJECT_NUMBER         = 0.12.GIT
-OUTPUT_DIRECTORY       = ../doc/api
+OUTPUT_DIRECTORY       = api
 CREATE_SUBDIRS         = NO
 OUTPUT_LANGUAGE        = English
 BRIEF_MEMBER_DESC      = YES
@@ -26,7 +26,7 @@ ABBREVIATE_BRIEF       = "The $name class" \
 ALWAYS_DETAILED_SEC    = NO
 INLINE_INHERITED_MEMB  = NO
 FULL_PATH_NAMES        = YES
-STRIP_FROM_PATH        = .
+STRIP_FROM_PATH        = @api_srcdir@
 STRIP_FROM_INC_PATH    = 
 SHORT_NAMES            = NO
 JAVADOC_AUTOBRIEF      = YES
@@ -90,7 +90,7 @@ WARN_LOGFILE           =
 # configuration options related to the input files
 #---------------------------------------------------------------------------
 
-INPUT                  = .
+INPUT                  = @api_srcdir@
 INPUT_ENCODING         = UTF-8
 FILE_PATTERNS          = *.c \
                          *.h \

doc/Makefile

@@ -56,6 +56,8 @@ MAN_DOCS-$(CONFIG_XMLTO) += \
 PDF_DOCS-$(CONFIG_JW) += \
  manual.pdf
 
+API_DOCS-$(CONFIG_DOXYGEN) += \
+ api/doxygen
 
 #############################################################################
 ## Set the default doc rules
@@ -63,11 +65,13 @@ PDF_DOCS-$(CONFIG_JW) += \
 MAN_DOCS  = $(MAN_DOCS-yes)
 HTML_DOCS = $(HTML_DOCS-yes)
 PDF_DOCS  = $(PDF_DOCS-yes)
+API_DOCS  = $(API_DOCS-yes)
 
 txt:  $(TXT_DOCS_NOINSTALL)
 html: txt $(HTML_DOCS)
 pdf:  txt $(PDF_DOCS)
 man:  txt $(MAN_DOCS)
+api:  $(API_DOCS)
 
 all-docs: man html pdf
 
@@ -99,7 +103,6 @@ clean-local:
 # TODO: perl.pod should be pod2ized during make install. --pasky
 install-local:
 
-
 #############################################################################
 # Generated asciidoc files
 
@@ -151,6 +154,9 @@ quiet_cmd_pod2html = ' [$(LINK_COLOR)POD2HTML$(END_COLOR)]   $(RELPATH)$@'
 quiet_cmd_asciidoc = ' [$(LINK_COLOR)ASCIIDOC$(END_COLOR)]   $(RELPATH)$@'
       cmd_asciidoc = $(ASCIIDOC) $(ASCIIDOC_FLAGS) -b $(call backend) -d $(call doctype) -o $@ $<
 
+ quiet_cmd_doxygen = ' [$(LINK_COLOR)DOXYGEN$(END_COLOR)]   $(RELPATH)$@'
+       cmd_doxygen = $(DOXYGEN) $(2)
+
 # Based on $@ find out asciidoc doctype or backend + xmlto output dir.
 doctype = $(if $(findstring .1.,$@)$(findstring .5.,$@),manpage,book)
 backend = $(if $(findstring .xml,$@),docbook,xhtml11)
@@ -199,5 +205,11 @@ man_hack = sed "s/^\(\.TH \"ELINKS[^\"]*\" [0-9] \).*/\1\"$(1)\" \"$(MAN_DATE)\"
 perl-%.html: %.pl
 	$(call cmd,pod2html)
 
+Doxyfile: $(srcdir)Doxyfile.in $(top_srcdir)/configure.in
+	cd $(top_builddir) && \
+	CONFIG_FILES="$(RELPATH)$@" CONFIG_HEADERS= $(SHELL) ./config.status
+
+api/doxygen: Doxyfile $(shell find $(top_srcdir)/src/ -name '*.[ch]' -o -name options.inc -o -name 'actions-*.inc' | sort)
+	$(call cmd,doxygen,$<)
 
 include $(top_srcdir)/Makefile.lib