libsysdecode: PROT_MAX() decoding bug

[sigsys_gmail.com]

Summary

Small bug with with the regular protection bits not being decoded when there's a PROT_MAX.

Test Plan

Doesn't seem like anything uses explicit PROT_MAX()s in base. So here's a sample program to truss.

#include <stddef.h>
#include <sys/mman.h>
#include <sys/param.h>

int main() {
	int prots[] = { PROT_NONE, PROT_READ, PROT_WRITE, PROT_EXEC, PROT_READ|PROT_WRITE, PROT_READ|PROT_WRITE|PROT_EXEC };
	for (size_t i = 0; i < nitems(prots); i++)
		for (size_t j = 0; j < nitems(prots); j++)
			mmap(NULL, PAGE_SIZE, prots[i] | PROT_MAX(prots[j]), MAP_ANON, -1, 0);
	return (0);
}

[kaktus]

.Good catch, tanks.