More windows fixes

- Designated initializer don't work in C++ code for MSVC

- munmap signature moved to the header

ethash.h

@@ -73,7 +73,7 @@ static inline void ethash_h256_reset(ethash_h256_t *hash)
 // have to provide all 32 values. If you don't provide all the rest
 // will simply be unitialized (not guranteed to be 0)
 #define ethash_h256_static_init(...)			\
-	{.b = {__VA_ARGS__} }
+	{ {__VA_ARGS__} }
 
 struct ethash_light;
 typedef struct ethash_light* ethash_light_t;

mmap.h

@@ -39,6 +39,7 @@
 #define MAP_FAILED    ((void *) -1)
 
 void *mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
+void munmap(void *addr, size_t length);
 #else // posix, yay! ^_^
 #include <sys/mman.h>
 #endif

mmap_win32.c

@@ -74,7 +74,7 @@ void *mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset
 	return ret;
 }
 
-static void munmap(void *addr, size_t length)
+void munmap(void *addr, size_t length)
 {
 	UnmapViewOfFile(addr);
 	/* ruh-ro, we leaked handle from CreateFileMapping() ... */