print $data;;

#some "random stuff" @include "some file" did you parse that?
#more 'random' stuff @include 'another file' you sure?
#and more random stuff @include yet\ another\ file positive?

print for $data =~ m[\@include\s('[^']+'|"[^"]+"|.+?(?<!\\))\s]g;;
"some file"
'another file'
yet\ another\ file

##</code><code>##

m[
  \@include \s       ## the introducer followed by a space
  (                  ## capture
      '[^']+'        ## A single quoted string with no embedded single quotes
  |                  ## or
      "[^"]+"        ## a double quoted string with no embedded double quotes
  |                  ## or
      .+? (?<!\\)    ## a min length string that ends in a space that isn't escaped
  )
  \s
]gx;;