'Drug cocktail' to fix /tmp bugs

I doubt that. The difference between signed and unsigned shows up mainly in comparisons. The result of an expression cast to unsigned (e.g. pointer arithmetic) is generally the same whether you use unsigned modulo arithmetic or two's complement. For example, without overflow detection,

char *buffer;
uint32_t x = 4294967295; // 2**32 - 1
buffer[x];

has exactly the same effect on 32-bit platforms as

char *buffer;
int32_t x = -1;
buffer[x];

The first version does at least have the marginal advantage that you only need to check the upper boundary, provided the lower boundary is zero.