recompiling problems when linking

[Ryan Liu]

All,

Now I have meet a strange problems.
When all the files have been compiled and when linking, make always
recompiles some files. I don't know why. Would you mind giving some
suggestion?
The following is the recompiling error?

***************************************************
collect: recompiling Time-data.cpp
In file included from
/opt/exp/gnu/sparc-sun-solaris2.8/include/c++/3.3.1/backward/iostream.h:31,
from ../../../sk/src/nih/errors.h:64,
from ../../../sk/src/nih/Object.h:167,
from Time-data.h:29,
from Time-data.cpp:23:
/opt/exp/gnu/sparc-sun-solaris2.8/include/c++/3.3.1/backward/backward_warnin
g.h:32:2: warning: #warning This file includes at least one deprecated or
antiquated header. Please consider using one of the 32 headers found in
section 17.4.1.2 of the C++ standard. Examples include substituting the <X>
header for the <X.h> header for C++ includes, or <sstream> instead of the
deprecated header <strstream.h>. To disable this warning
use -Wno-deprecated.
***************************************************

Thank you in advance.

Ryan