avoid potential crash with EmuDirectory if we somehow got no argv or an empty path

src/CP15.cpp

@@ -27,7 +27,6 @@
 // this was measured to be close to hardware average
 // a value of 1 would represent a perfect cache, but that causes
 // games to run too fast, causing a number of issues
-// code cache timing can get as low as 3
 const int kDataCacheTiming = 2;
 const int kCodeCacheTiming = 5;
 

src/libui_sdl/main.cpp

@@ -1315,7 +1315,7 @@ void OnOpenFile(uiMenuItem* item, uiWindow* window, void* blarg)
         EmuRunning = prevstatus;
         return;
     }
-    
+
     int pos = strlen(file)-1;
     while (file[pos] != '/' && file[pos] != '\\' && pos > 0) pos--;
     strncpy(Config::LastROMFolder, file, pos);
@@ -1566,6 +1566,7 @@ int main(int argc, char** argv)
     printf("melonDS " MELONDS_VERSION "\n");
     printf(MELONDS_URL "\n");
 
+    if (argc > 0 && strlen(argv[0]) > 0)
     {
         int len = strlen(argv[0]);
         while (len > 0)
@@ -1578,6 +1579,11 @@ int main(int argc, char** argv)
         strncpy(EmuDirectory, argv[0], len);
         EmuDirectory[len] = '\0';
     }
+    else
+    {
+        EmuDirectory = new char[2];
+        strcpy(EmuDirectory, ".");
+    }
 
     // http://stackoverflow.com/questions/14543333/joystick-wont-work-using-sdl
     SDL_SetHint(SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS, "1");