Expected unqualified-id before 'const'

Hi,

I am trying to build as a framework an opensource c/c++ librairy (cximage) under MacOs.
I was able to fix a few minor problems, some other I was helped with...
But I still have a recurrent problem I can't understand.
I receive a lot of errors of that kind :

error: unexpected unqualified-id before 'const'
error: expected ')' before 'const'

Here are the lines that return this error while compiling (in a .h header file) :

short ntohs(const short word);
short ntohl(const long dword);

Do you have any idea of what the problem is here?

Thank your.