Pay close attention to the bit about being generated on a WAMP system. This is clearly an issue with PHP using a faulty random-number generator on the Windows platform, and not a general fault that necessarily exists in all programming languages' random number generators. (Just for the record: Windows has a number of random number generator functions in its cryptographic libraries, some of which are on-par with those that ship with *nix. It's just that PHP on Windows isn't using them the right way)
Yes, glibc in particular uses a very nice PRNG with 992 bits of internal state and good randomness of high and low bits, though it is not cryptographically strong like /dev/urandom. I don't know what one gets on Windows, but from the graph it looks like it's got some tricky squaring thing in it that turns out not to be very good.
