Fixes #2022, do not resume on Android when surfaceChanged

If the app is in landscape mode and the user presses the power button, a pause
is followed immediately by a surfaceChanged event because the lock screen
is shown in portrait mode. This triggers a "false" resume.
So, we just pause and resume following the onWindowFocusChanged events.

Also, wait for SDL_APP_WILLENTERBACKGROUND and SDL_APP_DIDENTERBACKGROUND before
blocking the event pump.

src/loadso/beos/SDL_sysloadso.c

@@ -0,0 +1,71 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+#ifdef SDL_LOADSO_BEOS
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+/* System dependent library loading routines                           */
+
+#include <stdio.h>
+#include <be/kernel/image.h>
+
+#include "SDL_loadso.h"
+
+void *
+SDL_LoadObject(const char *sofile)
+{
+    void *handle = NULL;
+    image_id library_id = load_add_on(sofile);
+    if (library_id < 0) {
+        SDL_SetError(strerror((int) library_id));
+    } else {
+        handle = (void *) (library_id);
+    }
+    return (handle);
+}
+
+void *
+SDL_LoadFunction(void *handle, const char *name)
+{
+    void *sym = NULL;
+    image_id library_id = (image_id) handle;
+    status_t rc =
+        get_image_symbol(library_id, name, B_SYMBOL_TYPE_TEXT, &sym);
+    if (rc != B_NO_ERROR) {
+        SDL_SetError(strerror(rc));
+    }
+    return (sym);
+}
+
+void
+SDL_UnloadObject(void *handle)
+{
+    image_id library_id;
+    if (handle != NULL) {
+        library_id = (image_id) handle;
+        unload_add_on(library_id);
+    }
+}
+
+#endif /* SDL_LOADSO_BEOS */
+
+/* vi: set ts=4 sw=4 expandtab: */

src/loadso/dlopen/SDL_sysloadso.c

@@ -0,0 +1,74 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+#ifdef SDL_LOADSO_DLOPEN
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+/* System dependent library loading routines                           */
+
+#include <stdio.h>
+#include <dlfcn.h>
+
+#include "SDL_loadso.h"
+
+void *
+SDL_LoadObject(const char *sofile)
+{
+    void *handle = dlopen(sofile, RTLD_NOW|RTLD_LOCAL);
+    const char *loaderror = (char *) dlerror();
+    if (handle == NULL) {
+        SDL_SetError("Failed loading %s: %s", sofile, loaderror);
+    }
+    return (handle);
+}
+
+void *
+SDL_LoadFunction(void *handle, const char *name)
+{
+    void *symbol = dlsym(handle, name);
+    if (symbol == NULL) {
+        /* append an underscore for platforms that need that. */
+        size_t len = 1 + SDL_strlen(name) + 1;
+        char *_name = SDL_stack_alloc(char, len);
+        _name[0] = '_';
+        SDL_strlcpy(&_name[1], name, len);
+        symbol = dlsym(handle, _name);
+        SDL_stack_free(_name);
+        if (symbol == NULL) {
+            SDL_SetError("Failed loading %s: %s", name,
+                         (const char *) dlerror());
+        }
+    }
+    return (symbol);
+}
+
+void
+SDL_UnloadObject(void *handle)
+{
+    if (handle != NULL) {
+        dlclose(handle);
+    }
+}
+
+#endif /* SDL_LOADSO_DLOPEN */
+
+/* vi: set ts=4 sw=4 expandtab: */

src/loadso/dummy/SDL_sysloadso.c

@@ -0,0 +1,54 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+#if defined(SDL_LOADSO_DUMMY) || defined(SDL_LOADSO_DISABLED)
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+/* System dependent library loading routines                           */
+
+#include "SDL_loadso.h"
+
+void *
+SDL_LoadObject(const char *sofile)
+{
+    const char *loaderror = "SDL_LoadObject() not implemented";
+    SDL_SetError("Failed loading %s: %s", sofile, loaderror);
+    return (NULL);
+}
+
+void *
+SDL_LoadFunction(void *handle, const char *name)
+{
+    const char *loaderror = "SDL_LoadFunction() not implemented";
+    SDL_SetError("Failed loading %s: %s", name, loaderror);
+    return (NULL);
+}
+
+void
+SDL_UnloadObject(void *handle)
+{
+    /* no-op. */
+}
+
+#endif /* SDL_LOADSO_DUMMY || SDL_LOADSO_DISABLED */
+
+/* vi: set ts=4 sw=4 expandtab: */

src/loadso/windows/SDL_sysloadso.c

@@ -0,0 +1,72 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+#ifdef SDL_LOADSO_WINDOWS
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+/* System dependent library loading routines                           */
+
+#include "../../core/windows/SDL_windows.h"
+
+#include "SDL_loadso.h"
+
+void *
+SDL_LoadObject(const char *sofile)
+{
+    LPTSTR tstr = WIN_UTF8ToString(sofile);
+    void *handle = (void *) LoadLibrary(tstr);
+    SDL_free(tstr);
+
+    /* Generate an error message if all loads failed */
+    if (handle == NULL) {
+        char errbuf[512];
+        SDL_strlcpy(errbuf, "Failed loading ", SDL_arraysize(errbuf));
+        SDL_strlcat(errbuf, sofile, SDL_arraysize(errbuf));
+        WIN_SetError(errbuf);
+    }
+    return handle;
+}
+
+void *
+SDL_LoadFunction(void *handle, const char *name)
+{
+    void *symbol = (void *) GetProcAddress((HMODULE) handle, name);
+    if (symbol == NULL) {
+        char errbuf[512];
+        SDL_strlcpy(errbuf, "Failed loading ", SDL_arraysize(errbuf));
+        SDL_strlcat(errbuf, name, SDL_arraysize(errbuf));
+        WIN_SetError(errbuf);
+    }
+    return symbol;
+}
+
+void
+SDL_UnloadObject(void *handle)
+{
+    if (handle != NULL) {
+        FreeLibrary((HMODULE) handle);
+    }
+}
+
+#endif /* SDL_LOADSO_WINDOWS */
+
+/* vi: set ts=4 sw=4 expandtab: */