system.h: add section for tcc

#  define CURLSYS_TYPEOF_CURL_SOCKLEN_T int

#  define CURLSYS_SIZEOF_CURL_SOCKLEN_T 4

#elif defined(__TINYC__) /* also known as tcc */

#  define CURLSYS_SIZEOF_LONG           4

#  define CURLSYS_TYPEOF_CURL_OFF_T     long long

#  define CURLSYS_FORMAT_CURL_OFF_T     "lld"

#  define CURLSYS_FORMAT_CURL_OFF_TU    "llu"

#  define CURLSYS_SIZEOF_CURL_OFF_T     8

#  define CURLSYS_SUFFIX_CURL_OFF_T     LL

#  define CURLSYS_SUFFIX_CURL_OFF_TU    ULL

#  define CURLSYS_TYPEOF_CURL_SOCKLEN_T socklen_t

#  define CURLSYS_PULL_SYS_TYPES_H      1

#  define CURLSYS_PULL_SYS_SOCKET_H     1

/* ===================================== */

/*    KEEP MSVC THE PENULTIMATE ENTRY    */

/* ===================================== */