In the case of computer programs, but not Stephen King novels, in the US there is 17 USC 117 to consider which includes this: > (a) Making of Additional Copy o

In the case of computer programs, but not Stephen King novels, in the US there is 17 USC 117 to consider which includes this: > (a) Making of Additional Copy or Adaptation by Owner of Copy.—Notwithstanding the provisions of section 106, it is not an infringement for the owner of a copy of a computer program to make or authorize the making of another copy or adaptation of that computer program provided: > (1)that such a new copy or adaptation is created as an essential step in the utilization of the computer program in conjunction with a machine and that it is used in no other manner, or > (2)that such new copy or adaptation is for archival purposes only and that all archival copies are destroyed in the event that continued possession of the computer program should cease to be rightful. That should cover most likely scenarios of someone combining programs and/or libraries from various sources on their own computer as long as they own the particular copies of those programs and/or libraries that they are combining.