Remove platform-specific examples (Ref PR#2); add single platform check block in example.c

example.c

+#include <stdio.h>
+#include <string.h>
+
+#if defined (_WIN32) || defined (_WIN64)
+#define TRAY_WINAPI 1
+#elif defined (__linux__) || defined (linux) || defined (__linux)
+#define TRAY_APPINDICATOR 1
+#elif defined (__APPLE__) || defined (__MACH__)
+#define TRAY_APPKIT 1
+#endif
+
+#include "tray.h"
+
+#if TRAY_APPINDICATOR
+#define TRAY_ICON1 "indicator-messages"
+#define TRAY_ICON2 "indicator-messages-new"
+#elif TRAY_APPKIT
+#define TRAY_ICON1 "icon.png"
+#define TRAY_ICON2 "icon.png"
+#elif TRAY_WINAPI
+#define TRAY_ICON1 "icon.ico"
+#define TRAY_ICON2 "icon.ico"
+#endif
+
+static struct tray tray;
+
+static void toggle_cb(struct tray_menu *item) {
+  printf("toggle cb\n");
+  item->checked = !item->checked;
+  tray_update(&tray);
+}
+
+static void hello_cb(struct tray_menu *item) {
+  (void)item;
+  printf("hello cb\n");
+  if (strcmp(tray.icon, TRAY_ICON1) == 0) {
+    tray.icon = TRAY_ICON2;
+  } else {
+    tray.icon = TRAY_ICON1;
+  }
+  tray_update(&tray);
+}
+
+static void quit_cb(struct tray_menu *item) {
+  (void)item;
+  printf("quit cb\n");
+  tray_exit();
+}
+
+static void submenu_cb(struct tray_menu *item) {
+  (void)item;
+  printf("submenu: clicked on %s\n", item->text);
+  tray_update(&tray);
+}
+
+// Test tray init
+static struct tray tray = {
+    .icon = TRAY_ICON1,
+    .menu =
+        (struct tray_menu[]){
+            {.text = "Hello", .cb = hello_cb},
+            {.text = "Checked", .checked = 1, .cb = toggle_cb},
+            {.text = "Disabled", .disabled = 1},
+            {.text = "-"},
+            {.text = "SubMenu",
+             .submenu =
+                 (struct tray_menu[]){
+                     {.text = "FIRST", .checked = 1, .cb = submenu_cb},
+                     {.text = "SECOND",
+                      .submenu =
+                          (struct tray_menu[]){
+                              {.text = "THIRD",
+                               .submenu =
+                                   (struct tray_menu[]){
+                                       {.text = "7", .cb = submenu_cb},
+                                       {.text = "-"},
+                                       {.text = "8", .cb = submenu_cb},
+                                       {.text = NULL}}},
+                              {.text = "FOUR",
+                               .submenu =
+                                   (struct tray_menu[]){
+                                       {.text = "5", .cb = submenu_cb},
+                                       {.text = "6", .cb = submenu_cb},
+                                       {.text = NULL}}},
+                              {.text = NULL}}},
+                     {.text = NULL}}},
+            {.text = "-"},
+            {.text = "Quit", .cb = quit_cb},
+            {.text = NULL}},
+};
+
+int main() {
+  if (tray_init(&tray) < 0) {
+    printf("failed to create tray\n");
+    return 1;
+  }
+  while (tray_loop(1) == 0) {
+    printf("iteration\n");
+  }
+  return 0;
+}