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.
 +

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/commands.h

@@ -206,6 +206,7 @@ void CMD_BugOpts(F_CMD_ARGS);
 void CMD_BusyCursor(F_CMD_ARGS);
 void CMD_ButtonState(F_CMD_ARGS);
 void CMD_ButtonStyle(F_CMD_ARGS);
+void CMD_Capabilities(F_CMD_ARGS);
 void CMD_ChangeDecor(F_CMD_ARGS);
 void CMD_ChangeMenuStyle(F_CMD_ARGS);
 void CMD_CleanupColorsets(F_CMD_ARGS);

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;