fix export, fix LD path

cl-rng.asd

@@ -9,5 +9,6 @@
   :depends-on (:cffi)
   :components ((:file "package")
 	       (:file "ffi")
+	       (:file "crandom")
                (:file "urandom")
 	       (:file "cl-rng")))

ffi.lisp

@@ -2,7 +2,7 @@
 (in-package #:cl-rng-ffi)
 
 (define-foreign-library libsrng
-  (:unix (:or "libsrng.so" "libsrng" "./libsrng.so"))
+  (:unix (:or "libsrng.so" "libsrng" "./libsrng.so" "/usr/lib/libsrng.so" "/usr/local/lib/libsrng.so"))
   (t (:default "libsrng")))
 
 (use-foreign-library libsrng)