fix up scrypt-sse2 usage and detection.

To use SSE2, you need to pass a compiler flag "-DUSE_SSE2" when running configure

src/Makefile.am

@@ -231,6 +231,7 @@ crypto_libbitcoin_crypto_a_SOURCES = \
   crypto/ripemd160.cpp \
   crypto/ripemd160.h \
   crypto/scrypt.cpp \
+  crypto/scrypt-sse2.cpp \
   crypto/scrypt.h \
   crypto/sha1.cpp \
   crypto/sha1.h \

src/crypto/scrypt-sse2.cpp

@@ -33,6 +33,8 @@
 #include <string.h>
 #include <openssl/sha.h>
 
+#if defined(USE_SSE2)
+
 #include <emmintrin.h>
 
 static inline void xor_salsa8_sse2(__m128i B[4], const __m128i Bx[4])
@@ -134,3 +136,5 @@ void scrypt_1024_1_1_256_sp_sse2(const char *input, char *output, char *scratchp
 
 	PBKDF2_SHA256((const uint8_t *)input, 80, B, 128, 1, (uint8_t *)output, 32);
 }
+
+#endif

src/crypto/scrypt.cpp

@@ -28,7 +28,7 @@
  */
 
 #include "crypto/scrypt.h"
-//#include "util.h"
+#include "util.h"
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
@@ -293,7 +293,7 @@ void (*scrypt_1024_1_1_256_sp_detected)(const char *input, char *output, char *s
 void scrypt_detect_sse2()
 {
 #if defined(USE_SSE2_ALWAYS)
-    printf("scrypt: using scrypt-sse2 as built.\n");
+    LogPrintf("scrypt: using scrypt-sse2 as built.\n");
 #else // USE_SSE2_ALWAYS
     // 32bit x86 Linux or Windows, detect cpuid features
     unsigned int cpuid_edx=0;
@@ -311,12 +311,12 @@ void scrypt_detect_sse2()
     if (cpuid_edx & 1<<26)
     {
         scrypt_1024_1_1_256_sp_detected = &scrypt_1024_1_1_256_sp_sse2;
-        printf("scrypt: using scrypt-sse2 as detected.\n");
+        LogPrintf("scrypt: using scrypt-sse2 as detected.\n");
     }
     else
     {
         scrypt_1024_1_1_256_sp_detected = &scrypt_1024_1_1_256_sp_generic;
-        printf("scrypt: using scrypt-generic, SSE2 unavailable.\n");
+        LogPrintf("scrypt: using scrypt-generic, SSE2 unavailable.\n");
     }
 #endif // USE_SSE2_ALWAYS
 }

src/init.cpp

@@ -14,6 +14,7 @@
 #include "checkpoints.h"
 #include "compat/sanity.h"
 #include "consensus/validation.h"
+#include "crypto/scrypt.h"
 #include "key.h"
 #include "main.h"
 #include "miner.h"