spacedPrimesClosest
Gets the smallest prime number from a built-in array of primes which is larger than @num. This is used within GLib to calculate the optimum size of a #GHashTable.
The built-in array of primes ranges from 11 to 13845163 such that each prime is approximately 1.5-2 times the previous prime.
Return
the smallest prime number from a built-in array of primes which is larger than @num
Parameters
num
a #guint