Add libsodium to the tree and build what's needed from source.

git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@3859 ed5197a5-7fde-0310-b194-c3ffbd925b24

deps/libsodium/test/default/scalarmult5.c

@@ -0,0 +1,31 @@
+
+#define TEST_NAME "scalarmult5"
+#include "cmptest.h"
+
+static unsigned char alicesk[32] = { 0x77, 0x07, 0x6d, 0x0a, 0x73, 0x18, 0xa5,
+                                     0x7d, 0x3c, 0x16, 0xc1, 0x72, 0x51, 0xb2,
+                                     0x66, 0x45, 0xdf, 0x4c, 0x2f, 0x87, 0xeb,
+                                     0xc0, 0x99, 0x2a, 0xb1, 0x77, 0xfb, 0xa5,
+                                     0x1d, 0xb9, 0x2c, 0x2a };
+
+static unsigned char bobpk[32] = { 0xde, 0x9e, 0xdb, 0x7d, 0x7b, 0x7d, 0xc1,
+                                   0xb4, 0xd3, 0x5b, 0x61, 0xc2, 0xec, 0xe4,
+                                   0x35, 0x37, 0x3f, 0x83, 0x43, 0xc8, 0x5b,
+                                   0x78, 0x67, 0x4d, 0xad, 0xfc, 0x7e, 0x14,
+                                   0x6f, 0x88, 0x2b, 0x4f };
+
+int
+main(void)
+{
+    unsigned char k[32];
+    char          hex[65];
+    int           i;
+    int           ret;
+
+    ret = crypto_scalarmult(k, alicesk, bobpk);
+    assert(ret == 0);
+    sodium_bin2hex(hex, sizeof hex, k, sizeof k);
+    printf("%s\n", hex);
+
+    return 0;
+}