Rule 16.7 : possible const argument

These are used when implementing a C std routine which could use const arguments.

 ./src/alloc.c
./src/coldfire/uart_console_io_cf.c
./src/file_pos.c
./src/pa/fend.ppc.c
./src/mbstring.c
./src/misc_io.c
./src/printf.c
./src/sc/console_io_StarCore.c
./src/sc/file_io_StarCore.c
./src/scanf.c
./src/scanformat.c
./src/secure_error.c
./src/wprintf.c
./src/wprintformat.c
./src/wscanf.c