os2: add port files for SDL2-2.0.4 from Andrey Vasilkin

only geniconv/iconv.h (was from LGPL libiconv) is replaced with a generic
minimal iconv.h based on public knowledge.

src/loadso/os2/SDL_sysloadso.c

@@ -0,0 +1,79 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2016 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_internal.h"
+
+#ifdef SDL_LOADSO_OS2
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+/* System dependent library loading routines                           */
+
+#include "SDL_loadso.h"
+#include ".\core\os2\SDL_os2.h"
+
+#define INCL_DOSMODULEMGR
+#define INCL_DOSERRORS
+#include <os2.h>
+
+void *
+SDL_LoadObject(const char *sofile)
+{
+  ULONG      ulRC;
+  HMODULE    hModule;
+  PSZ        pszModName = OS2_UTF8ToSys( sofile );
+  CHAR       acError[256];
+
+  ulRC = DosLoadModule( &acError, sizeof(acError), pszModName, &hModule );
+  SDL_free( pszModName );
+  if ( ulRC != NO_ERROR )
+  {
+    SDL_SetError( "Failed loading, module: %s", pszModName );
+    return NULL;
+  }
+
+  return (void *)hModule;
+}
+
+void *
+SDL_LoadFunction(void *handle, const char *name)
+{
+  ULONG      ulRC;
+  PFN        pFN;
+
+  ulRC = DosQueryProcAddr( (HMODULE)handle, 0, name, &pFN );
+  if ( ulRC )
+  {
+    SDL_SetError( "Failed loading, procedure: %s", name );
+    return NULL;
+  }
+
+  return (void *)pFN;
+}
+
+void
+SDL_UnloadObject(void *handle)
+{
+  if ( handle != NULL )
+    DosFreeModule( (HMODULE)handle );
+}
+
+#endif /* SDL_LOADSO_OS2 */
+
+/* vi: set ts=4 sw=4 expandtab: */