Everything needed to run simple Rust programs (#40)

* Everything needed to run simple Rust programs

* Add IsDBCSLeadByte implementation

* Address PR comments

dll/bcrypt.cpp

@@ -0,0 +1,38 @@
+#include "common.h"
+
+#include <algorithm>
+#include <climits>
+#include <random>
+
+typedef PVOID BCRYPT_ALG_HANDLE;
+
+namespace bcrypt {
+
+using random_bytes_engine = std::independent_bits_engine<std::default_random_engine, CHAR_BIT, unsigned char>;
+
+NTSTATUS WIN_FUNC BCryptGenRandom(BCRYPT_ALG_HANDLE hAlgorithm, PUCHAR pbBuffer, ULONG cbBuffer, ULONG dwFlags) {
+	DEBUG_LOG("BCryptGenRandom(%p, %p, %lu, %lu)\n", hAlgorithm, pbBuffer, cbBuffer, dwFlags);
+	assert(hAlgorithm == nullptr);
+	assert(dwFlags == 0 || dwFlags == 2 /* BCRYPT_USE_SYSTEM_PREFERRED_RNG */);
+	random_bytes_engine rbe;
+	std::generate(pbBuffer, pbBuffer + cbBuffer, std::ref(rbe));
+	return STATUS_SUCCESS;
+}
+
+} // namespace bcrypt
+
+static void *resolveByName(const char *name) {
+	if (strcmp(name, "BCryptGenRandom") == 0)
+		return (void *)bcrypt::BCryptGenRandom;
+	return nullptr;
+}
+
+wibo::Module lib_bcrypt = {
+	(const char *[]){
+		"bcrypt",
+		"bcrypt.dll",
+		nullptr,
+	},
+	resolveByName,
+	nullptr,
+};