GHOST/Wayland: support dynamic loading libraries for Wayland

Add intern/wayland_dynload which is used when WITH_GHOST_WAYLAND_DYNLOAD
is enabled (off by default). When enabled, systems without Wayland
installed will fall back to X11.

This allows Blender to dynamically load:
- libwayland-client
- libwayland-cursor
- libwayland-egl
- libdecor-0 (when WITH_GHOST_WAYLAND_LIBDECOR is enabled).

1 files changed, 61 insertions, 0 deletions

diff --git a/intern/wayland_dynload/intern/wayland_dynload_egl.c b/intern/wayland_dynload/intern/wayland_dynload_egl.c
new file mode 100644
index 00000000000..b62adb6c90e
--- /dev/null
+++ b/intern/wayland_dynload/intern/wayland_dynload_egl.c
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup intern_wayland_dynload
+ *
+ * Wrapper functions for `<wayland-egl.h>`.
+ */
+
+#include <stdlib.h> /* `atexit`. */
+
+#include "wayland_dynload_API.h"
+#include "wayland_dynload_utils.h"
+
+#include "wayland_dynload_egl.h" /* Own include. */
+
+/* Public handle. */
+struct WaylandDynload_EGL wayland_dynload_egl = {NULL};
+
+static DynamicLibrary lib = NULL;
+
+bool wayland_dynload_egl_init(const bool verbose)
+{
+  /* Library paths. */
+  const char *paths[] = {
+      "libwayland-egl.so.0",
+      "libwayland-egl.so",
+  };
+  const int paths_num = sizeof(paths) / sizeof(*paths);
+  int path_found = 0;
+  if (!(lib = dynamic_library_open_array_with_error(paths, paths_num, verbose, &path_found))) {
+    return false;
+  }
+  if (atexit(wayland_dynload_egl_exit)) {
+    return false;
+  }
+
+#define WAYLAND_DYNLOAD_FN(symbol) \
+  if (!(wayland_dynload_egl.symbol = dynamic_library_find_with_error( \
+            lib, #symbol, paths[path_found]))) { \
+    return false; \
+  }
+#include "wayland_dynload_egl.h"
+#undef WAYLAND_DYNLOAD_FN
+
+  return true;
+}
+
+void wayland_dynload_egl_exit(void)
+{
+  if (lib != NULL) {
+    dynamic_library_close(lib); /*  Ignore errors. */
+    lib = NULL;
+  }
+}
+
+/* Validate local signatures against the original header. */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wredundant-decls"
+#define WAYLAND_DYNLOAD_VALIDATE
+#include "wayland_dynload_egl.h"
+#pragma GCC diagnostic pop