Apply the semantic patch rm-malloc-cast.cocci.

    for dir in library programs; do
        spatch --sp-file scripts/rm-malloc-cast.cocci --dir $dir \
        --in-place;
    done
diff --git a/library/md_wrap.c b/library/md_wrap.c
index 9554373..ed5a63e 100644
--- a/library/md_wrap.c
+++ b/library/md_wrap.c
@@ -395,7 +395,7 @@
 static void * ripemd160_ctx_alloc( void )
 {
     ripemd160_context *ctx;
-    ctx = (ripemd160_context *) polarssl_malloc( sizeof( ripemd160_context ) );
+    ctx = polarssl_malloc( sizeof( ripemd160_context ) );
 
     if( ctx == NULL )
         return( NULL );
@@ -491,7 +491,7 @@
 static void * sha1_ctx_alloc( void )
 {
     sha1_context *ctx;
-    ctx = (sha1_context *) polarssl_malloc( sizeof( sha1_context ) );
+    ctx = polarssl_malloc( sizeof( sha1_context ) );
 
     if( ctx == NULL )
         return( NULL );
@@ -700,7 +700,7 @@
 static void * sha256_ctx_alloc( void )
 {
     sha256_context *ctx;
-    ctx = (sha256_context *) polarssl_malloc( sizeof( sha256_context ) );
+    ctx = polarssl_malloc( sizeof( sha256_context ) );
 
     if( ctx == NULL )
         return( NULL );
@@ -906,7 +906,7 @@
 static void * sha512_ctx_alloc( void )
 {
     sha512_context *ctx;
-    ctx = (sha512_context *) polarssl_malloc( sizeof( sha512_context ) );
+    ctx = polarssl_malloc( sizeof( sha512_context ) );
 
     if( ctx == NULL )
         return( NULL );