[SV 46995] Strip leading/trailing space from variable names

[SV 46995] Strip leading/trailing space from variable names

* makeint.h: Change MAP_SPACE to MAP_NEWLINE, and add MAP_PATHSEP
and MAP_SPACE which is now MAP_BLANK|MAP_NEWLINE.  Create
NEW_TOKEN(), END_OF_TOKEN(), ISBLANK(), ISSPACE() macros.
* main.c (initialize_stopchar_map): Set MAP_NEWLINE only for
newline characters.
* Convert all uses of isblank() and isspace() to macros.
* Examine all uses of isblank() (doesn't accept newlines) and
change them wherever possible to ISSPACE() (does accept newlines).
* function.c (func_foreach): Strip leading/trailing space.
* variable.c (parse_variable_definition): Clean up.
* tests/scripts/functions/foreach: Test settings and errors.
* tests/scripts/functions/call: Rewrite to new-style.
* tests/scripts/misc/bs-nl: Add many more tests for newlines.