cmte/code: miscelaneous code for testing purposes @ cefa4e0c5cc9b2edc2e4f8af623d6db1645aa5ab

miscelaneous code for testing purposes

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