Fixed crash if initialization of EGL failed but was tried again later.

The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().

src/main/windows/SDL_windows_main.c

@@ -0,0 +1,201 @@
+/*
+    SDL_windows_main.c, placed in the public domain by Sam Lantinga  4/13/98
+
+    The WinMain function -- calls your program's main() function
+*/
+#include "SDL_config.h"
+
+#ifdef __WIN32__
+
+/* Include this so we define UNICODE properly */
+#include "../../core/windows/SDL_windows.h"
+
+/* Include the SDL main definition header */
+#include "SDL.h"
+#include "SDL_main.h"
+
+#ifdef main
+#  undef main
+#endif /* main */
+
+static void
+UnEscapeQuotes(char *arg)
+{
+    char *last = NULL;
+
+    while (*arg) {
+        if (*arg == '"' && (last != NULL && *last == '\\')) {
+            char *c_curr = arg;
+            char *c_last = last;
+
+            while (*c_curr) {
+                *c_last = *c_curr;
+                c_last = c_curr;
+                c_curr++;
+            }
+            *c_last = '\0';
+        }
+        last = arg;
+        arg++;
+    }
+}
+
+/* Parse a command line buffer into arguments */
+static int
+ParseCommandLine(char *cmdline, char **argv)
+{
+    char *bufp;
+    char *lastp = NULL;
+    int argc, last_argc;
+
+    argc = last_argc = 0;
+    for (bufp = cmdline; *bufp;) {
+        /* Skip leading whitespace */
+        while (SDL_isspace(*bufp)) {
+            ++bufp;
+        }
+        /* Skip over argument */
+        if (*bufp == '"') {
+            ++bufp;
+            if (*bufp) {
+                if (argv) {
+                    argv[argc] = bufp;
+                }
+                ++argc;
+            }
+            /* Skip over word */
+            lastp = bufp;
+            while (*bufp && (*bufp != '"' || *lastp == '\\')) {
+                lastp = bufp;
+                ++bufp;
+            }
+        } else {
+            if (*bufp) {
+                if (argv) {
+                    argv[argc] = bufp;
+                }
+                ++argc;
+            }
+            /* Skip over word */
+            while (*bufp && !SDL_isspace(*bufp)) {
+                ++bufp;
+            }
+        }
+        if (*bufp) {
+            if (argv) {
+                *bufp = '\0';
+            }
+            ++bufp;
+        }
+
+        /* Strip out \ from \" sequences */
+        if (argv && last_argc != argc) {
+            UnEscapeQuotes(argv[last_argc]);
+        }
+        last_argc = argc;
+    }
+    if (argv) {
+        argv[argc] = NULL;
+    }
+    return (argc);
+}
+
+/* Pop up an out of memory message, returns to Windows */
+static BOOL
+OutOfMemory(void)
+{
+    SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Fatal Error", "Out of memory - aborting", NULL);
+    return FALSE;
+}
+
+#if defined(_MSC_VER)
+/* The VC++ compiler needs main/wmain defined */
+# define console_ansi_main main
+# if UNICODE
+#  define console_wmain wmain
+# endif
+#endif
+
+/* WinMain, main, and wmain eventually call into here. */
+static int
+main_utf8(int argc, char *argv[])
+{
+    SDL_SetMainReady();
+
+    /* Run the application main() code */
+    return SDL_main(argc, argv);
+}
+
+/* This is where execution begins [console apps, ansi] */
+int
+console_ansi_main(int argc, char *argv[])
+{
+    /* !!! FIXME: are these in the system codepage? We need to convert to UTF-8. */
+    return main_utf8(argc, argv);
+}
+
+
+#if UNICODE
+/* This is where execution begins [console apps, unicode] */
+int
+console_wmain(int argc, wchar_t *wargv[], wchar_t *wenvp)
+{
+    int retval = 0;
+    char **argv = SDL_stack_alloc(char*, argc);
+    int i;
+
+    for (i = 0; i < argc; ++i) {
+        argv[i] = WIN_StringToUTF8(wargv[i]);
+    }
+
+    retval = main_utf8(argc, argv);
+
+    /* !!! FIXME: we are leaking all the elements of argv we allocated. */
+    SDL_stack_free(argv);
+
+    return retval;
+}
+#endif
+
+/* This is where execution begins [windowed apps] */
+int WINAPI
+WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine, int sw)
+{
+    char **argv;
+    int argc;
+    char *cmdline;
+
+    /* Grab the command line */
+    TCHAR *text = GetCommandLine();
+#if UNICODE
+    cmdline = WIN_StringToUTF8(text);
+#else
+    /* !!! FIXME: are these in the system codepage? We need to convert to UTF-8. */
+    cmdline = SDL_strdup(text);
+#endif
+    if (cmdline == NULL) {
+        return OutOfMemory();
+    }
+
+    /* Parse it into argv and argc */
+    argc = ParseCommandLine(cmdline, NULL);
+    argv = SDL_stack_alloc(char *, argc + 1);
+    if (argv == NULL) {
+        return OutOfMemory();
+    }
+    ParseCommandLine(cmdline, argv);
+
+    /* Run the main program */
+    main_utf8(argc, argv);
+
+    SDL_stack_free(argv);
+
+    SDL_free(cmdline);
+
+    /* Hush little compiler, don't you cry... */
+    return 0;
+}
+
+#endif /* __WIN32__ */
+
+/* vi: set ts=4 sw=4 expandtab: */