vhdl-compose-configuration-name

vhdl-compose-configuration-name is a variable defined in `vhdl-mode.el'.
Its value is

("\\(.*\\) \\(.*\\)" . "\\1_\\2_cfg")

Documentation:
Specifies how the configuration name is obtained.
The configuration name can be obtained by modifying the entity and/or
architecture name (e.g. attaching or stripping off a substring). The string
that is matched against the regexp is the concatenation of the entity and the
architecture name separated by a space. This gives access to both names (see
default setting as example).

FROM REGEXP is a regular expression matching the original name:
".*" matches the entire string
"\(...\)" matches a substring
TO STRING specifies the string to be inserted as new name:
"\&" means substitute entire matched text
"\N" means substitute what matched the Nth "\(...\)"
Examples:
".*" "\&" inserts original string
".*" "\&_i" attaches "_i" to original string
"\(.*\)_[io]$" "\1" strips off "_i" or "_o" from original string
".*" "foo" inserts constant string "foo"
".*" "" inserts empty string

You can customize this variable.