Added Doxygen aliases for pointing to OpenAL documentation.

Not found any online manpages however, so just placeholder.

Doxyfile

@@ -224,7 +224,9 @@ ALIASES                = \
     "requires_gles20=@xrefitem requires-gles20 \"Requires OpenGL ES 2.0\" \"Functionality requiring OpenGL ES 2.0 (not available in ES 3.0 and desktop OpenGL)\"" \
     "requires_es_extension=@xrefitem requires-es-extension \"Requires OpenGL ES extension\" \"Functionality requiring specific OpenGL ES extension\"" \
     "es_extension{2}=<a href=\"http://www.khronos.org/registry/gles/extensions/\1/\1_\2.txt\"><tt>\1_\2</tt></a>" \
-    "es_extension2{3}=<a href=\"http://www.khronos.org/registry/gles/extensions/\1/\3.txt\"><tt>\1_\2</tt></a>"
+    "es_extension2{3}=<a href=\"http://www.khronos.org/registry/gles/extensions/\1/\3.txt\"><tt>\1_\2</tt></a>" \
+    "fn_al{1}=`al\1()`" \
+    "def_al{1}=`AL_\1`"
 
 # This tag can be used to specify a number of word-keyword mappings (TCL only).
 # A mapping has the form "name=value". For example adding