Add ethash linux & windows build fixes

Godeps/_workspace/src/github.com/ethereum/ethash/ethash.go

@@ -127,12 +127,12 @@ func (l *Light) Verify(block pow.Block) bool {
 	return h256ToHash(ret.result).Big().Cmp(target) <= 0
 }
 
-func h256ToHash(in C.struct_ethash_h256) common.Hash {
+func h256ToHash(in C.ethash_h256_t) common.Hash {
 	return *(*common.Hash)(unsafe.Pointer(&in.b))
 }
 
-func hashToH256(in common.Hash) C.struct_ethash_h256 {
-	return C.struct_ethash_h256{b: *(*[32]C.uint8_t)(unsafe.Pointer(&in[0]))}
+func hashToH256(in common.Hash) C.ethash_h256_t {
+	return C.ethash_h256_t{b: *(*[32]C.uint8_t)(unsafe.Pointer(&in[0]))}
 }
 
 func (l *Light) getCache(blockNum uint64) *cache {

Godeps/_workspace/src/github.com/ethereum/ethash/ethashc.go

@@ -2,6 +2,7 @@ package ethash
 
 /*
 #cgo CFLAGS: -std=gnu99 -Wall
+#cgo windows CFLAGS: -mno-stack-arg-probe
 #cgo LDFLAGS: -lm
 
 #include "src/libethash/internal.c"

Godeps/_workspace/src/github.com/ethereum/ethash/src/libethash/io.h

@@ -49,7 +49,7 @@ enum ethash_io_rc {
 
 // small hack for windows. I don't feel I should use va_args and forward just
 // to have this one function properly cross-platform abstracted
-#if defined(_WIN32)
+#if defined(_WIN32) && !defined(__GNUC__)
 #define snprintf(...) sprintf_s(__VA_ARGS__)
 #endif
 

Godeps/_workspace/src/github.com/ethereum/ethash/src/libethash/util.h

@@ -26,11 +26,11 @@
 extern "C" {
 #endif
 
-#ifdef _MSC_VER
+//#ifdef _MSC_VER
 void debugf(char const* str, ...);
-#else
-#define debugf printf
-#endif
+//#else
+//#define debugf printf
+//#endif
 
 static inline uint32_t min_u32(uint32_t a, uint32_t b)
 {