Add semantic system include DIR through pkg-config. Usage: (fsh-semantic-pkg-config "gtk+-2.0 webkit-1.0..." 'c-mode)

fsh-semantic-pkg-config.el

(defun fsh-semantic-pkg-config (libs mode)
  "Add semantic system include DIR through pkg-config.

Usage: (fsh-semantic-pkg-config \"gtk+-2.0 QtGui QtNetwork...\" 'c-mode)"
  (let* ((pkg-cmd "pkg-config")
         (pkg-opt (format "--cflags %s" libs)))
    (setq result (shell-command-to-string (format "%s %s" pkg-cmd pkg-opt)))
    (dolist (str (split-string result))
      (if (string-match-p "^-I" str)
          (semantic-add-system-include (substring str 2 nil) mode)
          ))))