pollution: errnum
char* strerror(int errnum); 

pollution: a
pollution: b
int strcasecmp(const char* a, const char* b); 

pollution: a
pollution: b
pollution: n
int strncasecmp(const char* a, const char* b, size_t n); 

pollution: ffs
int ffs(int); 

pollution: signum
char* strsignal(int signum); 

pollution: ffsl
int ffsl(long int); 

pollution: ffsll
int ffsll(long long int);