Add support for building html documentation with Doxygen

- Add check during building
- `make html` builds documentation into ./docs/html
- Refine header checks in general

.gitignore

@@ -17,9 +17,12 @@ src/.dirstamp
 src/config.h*
 src/stamp-h1
 src/src
+docs/html
 
+.gdb_history
 Makefile
 Makefile.in
+Doxyfile
 aclocal.m4
 autom4te.cache
 compile

Makefile.am

@@ -1 +1,2 @@
+include docs/Makefile.am
 include src/Makefile.am

configure.ac

@@ -17,10 +17,8 @@ AX_CHECK_COMPILE_FLAG([-std=c11],
     [ CFLAGS+=" -std=c11" ],
     [ AC_MSG_ERROR([C compiler doesn't support C11 mode])] )
 
-# TODO: Update checks once we have code
-
 # Checks for header files.
-AC_CHECK_HEADERS([limits.h stddef.h stdint.h stdlib.h string.h sys/time.h unistd.h])
+AC_CHECK_HEADERS([assert.h math.h stdint.h stdlib.h stdbool.h stdio.h])
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_CHECK_HEADER_STDBOOL
@@ -70,6 +68,15 @@ if test x$lto = xyes; then
 fi
 
 AC_CONFIG_FILES([Makefile src/Makefile])
+
+# Documentation
+AC_CHECK_PROGS([DOXYGEN], [doxygen])
+if test -z "$DOXYGEN";
+    then AC_MSG_WARN([Doxygen not found - continuing without Doxygen support])
+fi
+AM_CONDITIONAL([HAVE_DOXYGEN], [test -n "$DOXYGEN"])
+AM_COND_IF([HAVE_DOXYGEN], [AC_CONFIG_FILES([docs/Doxyfile])])
+
 AC_OUTPUT
 
 AS_ECHO("")

docs/Makefile.am

@@ -0,0 +1,13 @@
+if HAVE_DOXYGEN
+
+doxyfile.stamp:
+	$(DOXYGEN) $(top_builddir)/docs/Doxyfile
+	echo Timestamp > doxyfile.stamp
+
+CLEANFILES = doxyfile.stamp
+
+html-local: doxyfile.stamp
+clean-local:
+	rm -rf $(top_builddir)/docs/html
+
+endif 

shell.nix

@@ -15,6 +15,6 @@ pkgs.stdenv.mkDerivation {
   name = "hvif-light";
 
   hardeningDisable = [ "all" ];
-  buildInputs = with pkgs; [ autoconf automake gcc clang-tools gdb valgrind-light pkg-config cairo ];
+  buildInputs = with pkgs; [ autoconf automake gcc clang-tools gdb valgrind-light pkg-config cairo doxygen ];
 
 }