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/zstream.cpp

@@ -76,8 +76,8 @@ bool zbuffer::use(std::streamoff Offset, std::streamoff Size)
 		return false;
 
     //Don't use a buffer already used;
-    if (m_Used)
-        return false;
+	if (m_Used)
+		return false;
 
 	// adjust file position
 	if (! m_ZipFile.seekg(Offset, ios::beg))