How to compile all *.c files in C++ mode

From: sbaranov2 (sbaranov_at_[hidden])
Date: 2005-01-26 15:22:12

The standard msvc.jam switches compiler to C mode for all *.c files 
(this adds -TC compiler option for *.c files and -TP for *.cpp files):

generators.register-c-compiler msvc.compile.c++ : CPP : OBJ : 
<toolset>msvc ;
generators.register-c-compiler msvc.compile.c : C : OBJ : 
<toolset>msvc ;

What's the easiest way to make *.c files use -TP compiler option 
without editing msvc.jam? (Supposedly from my project-root.jam?)

Thanks,
Stanislav