Fix handling of commas in arbitrary content in genexes.

As the comma is the parameter separator, it needs to be re-added
when evaluating to reconstruct arbitrary content.
Merge topic 'fix-genex-comma-parse' into next

05bf972 Fix handling of commas in arbitrary content in genexes.
Add string(MAKE_C_IDENTIFIER) subcommand.
Merge topic 'string-MAKE_C_IDENTIFIER-subcommand' into next

b6a4f93 Add string(MAKE_C_IDENTIFIER) subcommand.
Fix style.
Merge topic 'fix-style' into next

c70b9b5 Fix style.