civetweb.c: fix sprintf format specifier

Change %u to %lu and cast size_t to unsigned long to fix:

[src/civetweb.c:360]: (warning) %u in format string (no. 2) requires
 'unsigned int' but the argument type is 'size_t {aka unsigned long}'.
[src/civetweb.c:360]: (warning) %u in format string (no. 3) requires
 'unsigned int' but the argument type is 'unsigned long'.
[src/civetweb.c:360]: (warning) %u in format string (no. 4) requires
 'unsigned int' but the argument type is 'unsigned long'.
[src/civetweb.c:388]: (warning) %u in format string (no. 2) requires
 'unsigned int' but the argument type is 'size_t {aka unsigned long}'.
[src/civetweb.c:388]: (warning) %u in format string (no. 3) requires
 'unsigned int' but the argument type is 'unsigned long'.
[src/civetweb.c:388]: (warning) %u in format string (no. 4) requires
 'unsigned int' but the argument type is 'unsigned long'.
[src/civetweb.c:414]: (warning) %u in format string (no. 2) requires
 'unsigned int' but the argument type is 'size_t {aka unsigned long}'.
[src/civetweb.c:414]: (warning) %u in format string (no. 3) requires
 'unsigned int' but the argument type is 'unsigned long'.
[src/civetweb.c:414]: (warning) %u in format string (no. 4) requires
 'unsigned int' but the argument type is 'unsigned long'.
[src/civetweb.c:421]: (warning) %u in format string (no. 2) requires
 'unsigned int' but the argument type is 'size_t {aka unsigned long}'.
[src/civetweb.c:421]: (warning) %u in format string (no. 3) requires
 'unsigned int' but the argument type is 'unsigned long'.
[src/civetweb.c:421]: (warning) %u in format string (no. 4) requires
 'unsigned int' but the argument type is 'unsigned long'.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
civetweb.c: fix sscanf format specifier

Fix for:
[src/civetweb.c:5626]: (warning) %d in format string (no. 2)
 requires 'int *' but the argument type is 'unsigned int *'.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>