CryptoPP hang on linux

After porting some code that use cryptopp from windows to slackware linux it hangs.
The hang code:
AutoSeededRandomPool rng(true);

The reason was that AutoSeededRandomPool use /dev/random which blocks until the data become available.
The problem was resolved using default constructor, which use /dev/urandom:
AutoSeededRandomPool rng;

Build 2.6.38.8 kernel for Slackware 13.37

extract kernel to /usr/src/linux-2.6.38.8
copy your .config to /usr/src/linux-2.6.38.8
cd to /usr/src/linux-2.6.38.8

make prepare
make scripts
make -j4 modules
make -j4 bzImage
make modules_install
make install
reboot