xgm gcc/clang fixes

[jprjr]

These fix a few minor errors reported by gcc/clang.

I used ducible to verify that binaries produced by Visual Studio are identical to the master branch.

[jprjr]

I won't have any more pushes to this PR. Like before, I verified that every commit produces the exact same binary as before, there's no functional changes, it's all changes for the preprocessor (and adding an itoa replacement for Linux/unix)

[bbbradsmith]

What does "gcc/clang spacing on integer constants" mean? I'm unclear what this fixes.

[jprjr]

I believe it has to do with how clang/gcc is parsing 0x400e-0x4008 - specifically because it ends with an e, the error doesn't show up on the other values that are strictly numeric, I added the spacing to the other values just so they're all uniform.

Example - here's a small C++ program:

#include <stdio.h>

int reg[0x100];

int main(void) {
    int i;
    for(i=0;i<0x100;i++) reg[i] = i;
    i = reg[0x400e-0x4008]; /* should return 6 */
    printf("r=%d\n",i);
    return 0;
}

And when I try to compile with clang:

clang++ demo.cpp
demo.cpp:8:19: error: invalid suffix '-0x4008' on integer constant
    i = reg[0x400e-0x4008]; /* should return 6 */
                  ^
1 error generated.

g++ gives a slightly better error message:

g++ demo.cpp
demo.cpp: In function 'int main()':
demo.cpp:8:13: error: unable to find numeric literal operator 'operator""-0x4008'
    8 |     i = reg[0x400e-0x4008]; /* should return 6 */
      |

When I add a space around the minus sign, it realizes it's meant to be a subtraction.

[jprjr]

Oh and just for completeness sake - when I add spaces around the minus sign:

#include <stdio.h>

int reg[0x100];

int main(void) {
    int i;
    for(i=0;i<0x100;i++) reg[i] = i;
    i = reg[0x400e - 0x4008]; /* should return 6 */
    printf("r=%d\n",i);
    return 0;
}

clang++ demo.cpp
./a.out
r=6

[bbbradsmith]

Thanks for the explanation. That's an extremely curious way to parse a hexadecimal value... surprised I've never encountered it before. I guess I need to be careful when ending one with E. :(