Bug #249: Improve implementation of function “launch_gv_cmd”
The error detection was adjusted with the commit 4127b554 ("add error checking") from 2020-12-24. * Improve the exception handling another bit by extending relevant case distinctions. * Move more code into the wrapper function “check”. * Omit a semicolon and an extra space character from passed commands. See also: Complete error handling for a dot program call https://github.com/coccinelle/coccinelle/issues/249 [Various coding style cleanups by Julia Lawall <Julia.Lawall@inria.fr>] Signed-off-by:Markus Elfring <elfring@users.sourceforge.net>