[sprintf] Wrong handling of "+ " flags

[stefano-zanotti-88]

The standard says:

If the space and + flags both appear, the space flag is ignored.

STB vs standard-conforming:

printf("%+ 10i", 1);   // "         1" vs "        +1"
printf("% +10i", 1);   // "         1" vs "        +1"
printf("%+ 10f", 1.0); // "  1.000000" vs " +1.000000"
printf("% +10f", 1.0); // "  1.000000" vs " +1.000000"
printf("%+ 10g", 1.0); // "         1" vs "        +1"
printf("% +10g", 1.0); // "         1" vs "        +1"
printf("%+ 10a", 1.0); // "       0x1.000000p+0" vs "      +0x1.000000p+0"
printf("% +10a", 1.0); // "       0x1.000000p+0" vs "      +0x1.000000p+0"

Fix: the stbsp__lead_sign() function should change the order of its checks: first negative, then plus, then space (now it checks negative, space, plus):

stb/stb_sprintf.h

Lines 294 to 307 in f056911

	static void stbsp__lead_sign(stbsp__uint32 fl, char *sign)
	{
	sign[0] = 0;
	if (fl & STBSP__NEGATIVE) {
	sign[0] = 1;
	sign[1] = '-';
	} else if (fl & STBSP__LEADINGSPACE) {
	sign[0] = 1;
	sign[1] = ' ';
	} else if (fl & STBSP__LEADINGPLUS) {
	sign[0] = 1;
	sign[1] = '+';
	}
	}