Added support for guile's native pointer type

Examples/test-suite/guile/argout_runme.scm

@@ -0,0 +1,16 @@
+;; tests support for native guile pointers
+;; https://www.gnu.org/software/guile/manual/html_node/Void-Pointers-and-Byte-Access.html
+(dynamic-call "scm_init_argout_module" (dynamic-link "./libargout"))
+
+(use-modules (srfi srfi-4) (system foreign))
+
+(define initial-value 42)
+(define some-s32-data (s32vector initial-value))
+
+(if (not (= (incp (bytevector->pointer some-s32-data)) initial-value))
+    (error "Didn't read s32 data" initial-value some-s32-data))
+
+(if (not (= (s32vector-ref some-s32-data 0) (+ initial-value 1)))
+    (error "Failed to increment s32 data" some-s32-data))
+
+(exit 0)