$var =~ /^#include\s*<([^>]+)>/;
$file_name = $1;
(match var (regex (concat beginning-of-line
"#include"
(zero-or-more-of white-space)
"<"
(save-contents-as file-name (one-or-more-of (any-char-but #\>)))
">")))
(match var (^ #include (* \s) < (save file-name (+ ([^ >))) >)