add ability to compile uniform arrays

* module/rnrs/bytevector.scm (rnrs):
* libguile/bytevectors.h:
* libguile/bytevectors.c (scm_uniform_array_to_bytevector): New function.

* libguile/unif.h:
* libguile/unif.c (scm_from_contiguous_typed_array): New function.

* libguile/vm-i-loader.c (load-array): New instruction, for loading byte
  data into uniform vectors. Currently it copies out the data, though in
  the future we could avoid that.

* module/language/assembly.scm (align-code): New exported function,
  aligns code on some boundary.
  (align-program): Use align-code.

* module/language/assembly/compile-bytecode.scm (write-bytecode): Support
  the load-array instruction.

* module/language/glil/compile-assembly.scm (dump-object): Dump uniform
  arrays. Neat :)

module/language/assembly/compile-bytecode.scm

@@ -24,6 +24,7 @@
   #:use-module (language assembly)
   #:use-module (system vm instruction)
   #:use-module (srfi srfi-4)
+  #:use-module (rnrs bytevector)
   #:use-module ((srfi srfi-1) #:select (fold))
   #:use-module ((system vm objcode) #:select (byte-order))
   #:export (compile-bytecode write-bytecode))
@@ -72,6 +73,10 @@
   (define (write-loader str)
     (write-loader-len (string-length str))
     (write-string str))
+  (define (write-bytevector bv)
+    (write-loader-len (bytevector-length bv))
+    ;; Ew!
+    (for-each write-byte (bytevector->u8-list bv)))
   (define (write-break label)
     (write-uint16-be (- (assq-ref labels label) (+ (get-addr) 2))))
   
@@ -113,6 +118,7 @@
         ((load-string ,str) (write-loader str))
         ((load-symbol ,str) (write-loader str))
         ((load-keyword ,str) (write-loader str))
+        ((load-array ,bv) (write-bytevector bv))
         ((define ,str) (write-loader str))
         ((br ,l) (write-break l))
         ((br-if ,l) (write-break l))