Corrected physfs.h installation for new directory layout (thanks, Patrice!).

CMakeLists.txt

@@ -362,7 +362,7 @@ INSTALL(TARGETS ${PHYSFS_INSTALL_TARGETS}
         RUNTIME DESTINATION bin
         LIBRARY DESTINATION lib
         ARCHIVE DESTINATION lib)
-INSTALL(FILES physfs.h DESTINATION include)
+INSTALL(FILES src/physfs.h DESTINATION include)
 
 FIND_PACKAGE(Doxygen)
 IF(DOXYGEN_FOUND)