emmalloc.c does a fair amount of type punning in order to access
the size of memory regions and traverse them.

Unfortunately, that can lead to unwanted optimizations.

This simple test case currently triggers a memory fault:

int main(void) {
    char * volatile p = malloc(1);
    p = realloc(p, 12);
    p = malloc(1);
    printf("%p\n", p);
}

Work around this by adding "-fno-strict-aliasing" when compiling
that file.