imult16 - integer multiplication with overflow checking

       imult16 does c=a*b and returns 1.

       In case of an integer overflow, imult16 leaves c alone and returns 0.

       imult16 - integer multiplication with overflow checking

umult16(3), imult32(3), imult64(3)

                                                                                                      imult16(3)

#include<libowfat/safemult.h>

       int imult16(int16 a,int16 b,int16* c);