Fixed getAbsoluteFilename under Linux in case the file does not exist. Did simply return an empty string, now it returns the original filename.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@1685 dfc29bdd-3216-0410-991c-e03cc46cb475

source/Irrlicht/CFileSystem.cpp

@@ -218,6 +218,8 @@ core::stringc CFileSystem::getAbsolutePath(const core::stringc& filename) const
 #elif (defined(_IRR_POSIX_API_) || defined(_IRR_OSX_PLATFORM_))
 	c8 fpath[4096];
 	p = realpath(filename.c_str(), fpath);
+	if (!p)
+		return filename;
 #endif
 
 	return core::stringc(p);