hi,
On the x86_64 platform we faced a problem of debugging modules using
KGDB. 
For working around the problem, we need the compile the file
'arch/x86_64/kernel/vsyscall.c' without the generation of debugging
information.
For this i moved the 'vsyscall.c' from the directory
'arch/x86_64/kernel' to a new directory 'arch/x86_64/kernel/vsyscall/' .
The make file in this new directory does not generate the debugging
information for the file 'vsyscall.c'.
Please let me know if there is some other way by which i can specify a
different set of compilation flags for a single file in the directory.
this will help me in not moving the file in a new directory.

Regards,
Mithlesh Thukral