doc: use autotoolized Doxyfile

This has several advantages:
* More simplified Makefile.am
* Actually used doxygen config is available as a file
* Building doc out-of-tree is possible

Signed-off-by: Alexander Stein <alexander.stein@mailbox.org>
[Bartosz: add a dependency on Doxygen to the doc target in Makefile]
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

.gitignore

@@ -10,6 +10,7 @@ doc
 # autotools stuff
 .deps/
 .libs/
+Doxyfile
 Makefile
 Makefile.in
 aclocal.m4

Doxyfile → Doxyfile.in

@@ -10,6 +10,7 @@
 
 # General configuration
 PROJECT_NAME           = libgpiod
+PROJECT_NUMBER         = @VERSION_STR@
 OUTPUT_DIRECTORY       = doc
 OUTPUT_LANGUAGE        = English
 EXTRACT_ALL            = NO
@@ -48,7 +49,7 @@ WARNINGS               = YES
 WARN_IF_UNDOCUMENTED   = YES
 WARN_FORMAT            =
 WARN_LOGFILE           =
-INPUT                  = include/gpiod.h
+INPUT                  = @top_srcdir@/include/gpiod.h @top_srcdir@/bindings/cxx/gpiod.hpp
 SOURCE_BROWSER         = YES
 INLINE_SOURCES         = NO
 REFERENCED_BY_RELATION = YES

Makefile.am

@@ -28,10 +28,8 @@ SUBDIRS += bindings
 
 if HAS_DOXYGEN
 
-doc:
-	@(cat Doxyfile; \
-		echo PROJECT_NUMBER = $(VERSION_STR); \
-		echo INPUT += bindings/cxx/gpiod.hpp) | doxygen -
+doc: Doxyfile
+	@doxygen Doxyfile
 .PHONY: doc
 
 clean-local:

configure.ac

@@ -207,6 +207,7 @@ if test "x$has_doxygen" = xfalse
 then
 	AC_MSG_NOTICE([doxygen not found - documentation cannot be generated])
 fi
+AM_COND_IF([HAS_DOXYGEN], [AC_CONFIG_FILES([Doxyfile])])
 
 if test "x$cross_compiling" = xno
 then