* init/job.c (job_config_environment): Function to generate an
environment table from a JobConfig, code largely moved from process.c
* init/job.h: Add protoyype.
(JOB_DEFAULT_ENVIRONMENT): List of environment variables to always
copy from the environment (moved from process.h)
* init/tests/test_job.c (test_config_environment): Add test case,
again largely copied from test_process.c
* init/process.c (process_environment): Call job_config_environment
instead of the code moved out.
* init/process.h (PROCESS_ENVIRONMENT): Move to job.h
* TODO: Update.