Ever wondered what all those pre #defined preprocessor constants expand to?Execute the following: gcc -dM -E - Sample output from Ubuntu 13.10 (gcc 4.8.1):shahada@pc-shahada:/usr/include$ gcc -dM -E - * Sample output from buildroot, ARM target, gcc 4.8.0:#define __ACCUM_EPSILON__ 0x1P-15K #define __ACCUM_FBIT__ 15 #define __ACCUM_IBIT__ 16 #define __ACCUM_MAX__ 0X7FFFFFFFP-15K #define __ACCUM_MIN__ (-0X1P15K-0X1P15K) #define __APCS_32__ 1 #define __arm__ 1 #define __ARM_ARCH 4 #define __ARM_A...