style: add window-property matching

Historically, window style matching relied on fvwm matching a windows
name or resource or class, etc., in a hard-coded order, with very little
means of being able to specify those properties.

With this change, it's now possible to specify the following attributes
a window should match against, either individually or in combination:

 - Resource
 - Class
 - Name
 - Icon
 - WindowID

For example:

  Style (Name foo, Class XTerm) Sticky

Would only make the window sticky if its name matched "foo", and its
class is "XTerm".

Existing style lines such as:

  Style foo Sticky

Still work as expected.

In addition, this change also removes the "PrintInfo style" command as
it is no longer useful with this change to styles.

doc/fvwm3_manpage_source.adoc

@@ -3451,8 +3451,6 @@ fvwm used. _verbose_ can be 1 or 2.
 +
 _nls_ which prints information on the locale catalogs that fvwm used
 +
-_style_ which prints information on fvwm styles. _verbose_ can be 1.
-+
 _bindings_ which prints information on all the bindings fvwm has: key
 and mouse bindings. _verbose_ has no effect with this option.
 +
@@ -4942,6 +4940,55 @@ For readability, the commands in this section are not sorted
 alphabetically. The description of the *Style* command can be found at
 the end of this section.
 
+The commands: *FocusStyle*, *Style*, and *WindowStyle* can accept optional
+conditional components to match some properties of a window.
+
+For example:
+
+....
+Style (Name mc) Sticky
+....
+
+Will make a window whose name matched 'mc' _Sticky_.
+
+....
+Style (Name mc, Class XTerm) StartIconic
+....
+
+This example will start an xterm(1) window whose WM_CLASS matches 'XTerm' and
+name is 'mc'.
+
+A valid list of properties to test against are:
+
+* Resource
+* Class
+* Name
+* Icon
+* WindowID
+
+The matching of the properties specified for any *Style* line are ANDed
+together, and for styles to be applied, *all* properties must match.
+
+**NOTE**: To destroy a style line with window properties, *DestroyStyle*
+should be used.  For example:
+
+....
+DestroyStyle (Name mc, Class XTerm)
+....
+
+It is not required to specify the style arguments when destroying a style,
+only the property components are required.
+
+Existing *Style* lines in the form:
+
+....
+Style Application* Sticky, StartIconic
+....
+
+are still supported, and their behaviour remains unchanged.
+
+'''
+
 *FocusStyle* _stylename_ _options_::
 	works exactly like the *Style* command, but accepts only the focus
 	policy related styles beginning with "FP". The prefix can be removed,

fvwm/builtins.c

@@ -2651,10 +2651,6 @@ void CMD_PrintInfo(F_CMD_ARGS)
 	{
 		FGettextPrintLocalePath(verbose);
 	}
-	else if (StrEquals(subject, "style"))
-	{
-		print_styles(verbose);
-	}
 	else if (StrEquals(subject, "ImageCache"))
 	{
 		PicturePrintImageCache(verbose);

fvwm/fvwm.h

@@ -570,15 +570,24 @@ typedef struct style_flags
 	unsigned initial_placement_done : 1;
 } style_flags;
 
+typedef struct style_id_flags
+{
+	unsigned has_name:1;
+	unsigned has_window_id:1;
+	unsigned has_class:1;
+	unsigned has_resource:1;
+	unsigned has_icon:1;
+	unsigned is_compatibility_mode:1;
+} style_id_flags;
+
 typedef struct style_id_t
 {
-	char *name;
 	XID window_id;
-	struct
-	{
-		unsigned has_name:1;
-		unsigned has_window_id:1;
-	} flags;
+	style_id_flags flags;
+	char *name;
+	char *class;
+	char *resource;
+	char *icon;
 } style_id_t;
 
 typedef struct snap_attraction_t
@@ -679,6 +688,14 @@ typedef struct window_style
 	unsigned has_icon_title_format_string : 1;
 } window_style;
 
+typedef struct window_style_list
+{
+	struct window_style_list	*next;
+	style_id_t			 flags;
+	window_style			*first_style;
+	window_style			*last_style;
+} window_style_list;
+
 typedef struct window_g
 {
 	rectangle frame;

fvwm/screen.h

@@ -444,6 +444,10 @@ typedef struct ScreenInfo
 		unsigned do_debug_randr : 1;
 	} bo; /* bug workaround control options */
 	struct
+	{
+		unsigned fvwm_style_v3 : 1;
+	} cap; /* Capabilities. */
+	struct
 	{
 		unsigned do_emulate_mwm : 1;
 		unsigned do_emulate_win : 1;