miscelaneous code for testing purposes

Douglas Andreani cefa4e0c5c libpng: add error handling to non existing file %!s(int64=5) %!d(string=hai) anos
libpng cefa4e0c5c libpng: add error handling to non existing file %!s(int64=5) %!d(string=hai) anos
pthread 1b74b0c461 initial pthread and q_thread_model %!s(int64=5) %!d(string=hai) anos
queue_thread_model ef3e64cec5 changes to output on q_thread_model %!s(int64=5) %!d(string=hai) anos
x11-random 4ebb33954c replace rand() for drand48() on x11-examples/worley=noise %!s(int64=5) %!d(string=hai) anos