Concatenate two strings in apache config

Question

In an apache config file how can i concatenate two strings?

For example:

"hello" + "world"
// "helloworld"

---

Why?

One might want to do this to handle large Headers such as a Content-Security-Policy below is an example of my CSP. You can see it is nicely formatted for maintainability but when being sent in the Headers it has unwanted whitespace.

Header set Content-Security-Policy "\
;default-src\
    'self'\
;child-src\
    'self'\
;connect-src\
    'self'\
;font-src\
    'self'\
    https://*.gstatic.com\
;form-action\
    'self';\
;frame-ancestors\
    'self'\
;frame-src\
    'self'\
;img-src\
    'self'\
    https://www.google.com/s2/favicons\
    https://www.google-analytics.com\
    https://*.gstatic.com\
    https://*.googleapis.com\
;object-src\
    'none'\
;script-src\
    'self'\
    'unsafe-eval'\
    https://www.google-analytics.com\
    https://*.googleapis.com\
;style-src\
    'self'\
    'unsafe-inline'\
    https://*.googleapis.com\
;\
"

Answer 1

I think you can declare variable like this : https://stackoverflow.com/a/15731921/6663198
Then, you can easily concatenate your variables