Added md_process() to MD layer for generic internal access to hash
process functions

Access to process functions is needed to reduce possible timing attacks
on SSL MAC checks. As SSL is set to move to using the dynamic MD layer,
the MD layer needs access to these process functions as well.
diff --git a/library/md4.c b/library/md4.c
index 82adcd8..6012526 100644
--- a/library/md4.c
+++ b/library/md4.c
@@ -76,7 +76,7 @@
     ctx->state[3] = 0x10325476;
 }
 
-static void md4_process( md4_context *ctx, const unsigned char data[64] )
+void md4_process( md4_context *ctx, const unsigned char data[64] )
 {
     uint32_t X[16], A, B, C, D;