Make the app icon work on macOS, Windows, and Linux.

Co-authored-by: Cursor <cursoragent@cursor.com>

Makefile

@@ -17,12 +17,15 @@ GTK_LIBS   := $(shell $(PKG_CONFIG) --libs gtk4)
 CFLAGS = -Wall -Wextra -Wno-deprecated-declarations $(GTK_CFLAGS)
 LIBS = $(GTK_LIBS) -lm
 
-# Windows (MSYS2 / MinGW): .exe suffix and no console window for the GUI.
+# Windows (MSYS2 / MinGW): .exe suffix, no console window, embed .ico.
 ifeq ($(OS),Windows_NT)
 TARGET = maturita.exe
 LIBS += -mwindows
+WINDRES ?= windres
+RC_OBJ = maturita_rc.o
 else
 TARGET = maturita
+RC_OBJ =
 # macOS Dock icon is set via AppKit (see macos_dock.c).
 ifeq ($(shell uname -s 2>/dev/null),Darwin)
 LIBS += -framework AppKit -framework Foundation
@@ -34,6 +37,7 @@ OBJ = $(SRC:.c=.o)
 
 ICON_SRC = assets/app-icon.png
 ICON_DST = assets/icons/hicolor/512x512/apps/maturita.png
+ICON_ICO = assets/app-icon.ico
 
 all: $(TARGET)
 
@@ -41,11 +45,19 @@ $(ICON_DST): $(ICON_SRC)
 	mkdir -p $(dir $@)
 	cp "$(ICON_SRC)" "$@"
 
+ifeq ($(OS),Windows_NT)
+$(RC_OBJ): maturita.rc $(ICON_ICO)
+	$(WINDRES) maturita.rc -o $(RC_OBJ)
+
+$(TARGET): $(SRC) $(ICON_DST) $(RC_OBJ)
+	$(CC) $(CFLAGS) -o $(TARGET) $(SRC) $(RC_OBJ) $(LIBS)
+else
 $(TARGET): $(SRC) $(ICON_DST)
 	$(CC) $(CFLAGS) -o $(TARGET) $(SRC) $(LIBS)
+endif
 
 clean:
-	rm -f $(TARGET) maturita.exe $(OBJ)
+	rm -f $(TARGET) maturita.exe $(OBJ) $(RC_OBJ) maturita_rc.o
 
 run: $(TARGET)
 	./$(TARGET)
@@ -61,6 +73,7 @@ bundle: $(TARGET)
 	@cp style.css dist/
 	@mkdir -p dist/icons/hicolor/512x512/apps
 	@cp "$(ICON_DST)" dist/icons/hicolor/512x512/apps/
+	@cp -R share dist/
 	@ldd $(TARGET) | grep -Ei '/(ucrt64|mingw64)/bin/' | awk '{print $$3}' \
 		| xargs -r -I{} cp -f {} dist/
 	@echo "Bundled into dist/ - run dist/$(TARGET)"