Add an option to control GtkDoc header generation

This allows explicit activation or deactivation of the GtkDoc header
generation.

This might allow to e.g. force enable it on distcheck.

configure.ac

@@ -123,7 +123,7 @@ AC_SUBST([pkgdatadir])
 # Documentation tools
 GEANY_CHECK_DOCUTILS
 GEANY_CHECK_DOXYGEN
-GEANY_CHECK_PYTHON
+GEANY_CHECK_GTKDOC_HEADER
 
 # libgeany
 GEANY_LIB_INIT

doc/Makefile.am

@@ -119,7 +119,7 @@ Doxyfile.stamp: Doxyfile Doxyfile-gi $(doxygen_sources)
 
 ALL_TARGETS = Doxyfile.stamp
 
-if WITH_PYTHON
+if ENABLE_GTKDOC_HEADER
 
 geany-gtkdoc.h: Doxyfile.stamp $(top_srcdir)/scripts/gen-api-gtkdoc.py
 	$(AM_V_GEN)$(top_srcdir)/scripts/gen-api-gtkdoc.py xml -d $(builddir) \

m4/geany-docutils.m4

@@ -70,29 +70,3 @@ AC_DEFUN([GEANY_CHECK_DOCUTILS_PDF],
 	AM_CONDITIONAL([WITH_RST2PDF], [test "x$geany_enable_pdf_docs" != "xno"])
 	GEANY_STATUS_ADD([Build PDF documentation], [$geany_enable_pdf_docs])
 ])
-
-dnl
-dnl GEANY_CHECK_PYTHON
-dnl For gtkdoc header generation
-dnl
-AC_DEFUN([GEANY_CHECK_PYTHON],
-[
-	AM_PATH_PYTHON([2.7], [], [])
-
-	have_python=no
-	AS_IF([test -n "$PYTHON"], [
-		AC_MSG_CHECKING([for python lxml package])
-		$PYTHON -c 'import lxml' 1>&2 2>/dev/null
-		AS_IF([test $? -eq 0], [
-			AC_MSG_RESULT([found])
-			have_python=yes
-		], [
-			AC_MSG_RESULT([not found])
-			have_python=no
-		])
-	])
-
-	AM_CONDITIONAL([WITH_PYTHON], [test "x$have_python" = "xyes"])
-	AM_COND_IF([WITH_PYTHON],
-		[GEANY_STATUS_ADD([Using Python version], [$PYTHON_VERSION])])
-])

m4/geany-gtkdoc-header.m4

+AC_DEFUN([_GEANY_CHECK_GTKDOC_HEADER_ERROR],
+[
+	AC_MSG_ERROR([GtkDoc header generation enabled but $1])
+])
+
+dnl GEANY_CHECK_GTKDOC_HEADER
+dnl checks for GtkDoc header generation requirements and define
+dnl ENABLE_GTKDOC_HEADER Automake conditional as appropriate
+AC_DEFUN([GEANY_CHECK_GTKDOC_HEADER],
+[
+	AC_REQUIRE([GEANY_CHECK_DOXYGEN])
+
+	AC_ARG_ENABLE([gtkdoc-header],
+			[AS_HELP_STRING([--enable-gtkdoc-header],
+					[generate the GtkDoc header suitable for GObject introspection [default=auto]])],
+			[geany_enable_gtkdoc_header="$enableval"],
+			[geany_enable_gtkdoc_header="auto"])
+
+	AS_IF([test "x$geany_enable_gtkdoc_header$geany_with_doxygen" = "xyesno"],
+	      [_GEANY_CHECK_GTKDOC_HEADER_ERROR([Doxygen support not available])],
+	      [test "x$geany_enable_gtkdoc_header" != "xno"],
+	[
+		dnl python
+		AM_PATH_PYTHON([2.7], [have_python=yes], [have_python=no])
+		dnl lxml module
+		AS_IF([test "x$have_python" = xyes],
+		      [have_python_and_lxml=yes
+		       AC_MSG_CHECKING([for python lxml package])
+		       AS_IF([$PYTHON -c 'import lxml' 2>&1 >/dev/null],
+		             [have_python_and_lxml=yes],
+		             [have_python_and_lxml=no])
+		       AC_MSG_RESULT([$have_python_and_lxml])],
+		      [have_python_and_lxml=no])
+		dnl final result
+		AS_IF([test "x$geany_enable_gtkdoc_header$have_python_and_lxml" = "xyesno"],
+		      [_GEANY_CHECK_GTKDOC_HEADER_ERROR([python or its lxml module not found])],
+		      [geany_enable_gtkdoc_header=yes])
+	])
+
+	AM_CONDITIONAL([ENABLE_GTKDOC_HEADER], [test "x$geany_enable_gtkdoc_header" = "xyes"])
+	GEANY_STATUS_ADD([Generate GtkDoc header], [$geany_enable_gtkdoc_header])
+])