Include missing sys/time.h

[kraj]

This is found when building for musl C library systems where sys/time.h is not included indirectly and select() and timeval structs are used

Fixes

../../git/tests/receive.c:64:17: error: variable has incomplete type 'struct timeval' 64 | struct timeval tvSelectTimeout; | ^ ../../git/tests/receive.c:64:9: note: forward declaration of 'struct timeval' 64 | struct timeval tvSelectTimeout; | ^ ../../git/tests/receive.c:67:2: error: call to undeclared function 'select'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 67 | select(0, NULL, NULL, NULL, &tvSelectTimeout); | ^