Implement and test mbedtls_mpi_mod_raw_random

In the basic/XXX=core test cases, use odd upper bounds, because the mod
version of random() only supports odd upper bounds (the upper bound is a
modulus and the mod modules only support odd moduli).

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/bignum_mod_raw.c b/library/bignum_mod_raw.c
index c98a1c1..fbd90bf 100644
--- a/library/bignum_mod_raw.c
+++ b/library/bignum_mod_raw.c
@@ -176,6 +176,18 @@
 
 /* BEGIN MERGE SLOT 6 */
 
+int mbedtls_mpi_mod_raw_random( mbedtls_mpi_uint *X,
+                                mbedtls_mpi_uint min,
+                                const mbedtls_mpi_mod_modulus *N,
+                                int (*f_rng)(void *, unsigned char *, size_t),
+                                void *p_rng )
+{
+    int ret = mbedtls_mpi_core_random( X, min, N->p, N->limbs, f_rng, p_rng );
+    if( ret != 0 )
+        return( ret );
+    return( mbedtls_mpi_mod_raw_to_mont_rep( X, N ) );
+}
+
 /* END MERGE SLOT 6 */
 
 /* BEGIN MERGE SLOT 7 */