X11 build fixups

- fixed -Werror=misleading-indentation warning
- fixed -Werror=nonnull-compare warning on xll and QT builds
- PNG_LIBPNG_VER backward compatibily changes
- giflib backward compatibily changes
- resolved some undefs for X11 build
- silenced some small compile warnings in JGE Makefile
- added -DTIXML_USE_STL to remaining build types (PSP had it added)
- fixed x11 Boost incompatibility issue part of #548
- reworked PrecompiledHeader.h platforms used

JGE/src/zipFS/zfsystem.h

@@ -258,8 +258,8 @@ inline void izfstream::open(const char * FilePath, filesystem * pFS) {
     if (pFS)
         m_pFS = pFS;
 
-	if (m_pFS != NULL)
-		m_pFS->Open(* this, FilePath);
+    if (m_pFS != NULL)
+        m_pFS->Open(* this, FilePath);
 }
 
 inline void izfstream::close() {