1. All '*.env' files in an 'environment.d' directory alongside each
potential 'environment' file will be parsed and added to the
environment.
2. For the purposes of configuration merging, an environment definition
exists at one level if either the 'environment' file is defined or
its corresponding 'environment.d' contains any valid '*.env' file.
3. Variable declarations of the form "VARIABLE=", with no following
value, will be written to the environment as empty strings.
Made all header files to have LABWC_ prefix in include guard identifers.
Converted from __LABWC_ in 35 include/ files.
Converted from __LAB_ in 5 include/ files.
Added LABWC prefix to 3 include/ files.
Added include guards to 3 include/ files.
The double underscores were removed since according to C standard
those "are always reserved for any use".
