Use X64 ASM ed25519 signatures on Linux/x64, which are about 10X faster. Will matter a lot for network controllers, not so much for other things.

ext/ed25519-amd64-asm/sc25519_to32bytes.c

@@ -0,0 +1,8 @@
+#include "sc25519.h"
+
+void sc25519_to32bytes(unsigned char r[32], const sc25519 *x)
+{
+  /* assuming little-endian */
+  int i;
+  for(i=0;i<32;i++) r[i] = i[(unsigned char *)x->v]; 
+}