Everything needed to run simple Rust programs (#40)

* Everything needed to run simple Rust programs

* Add IsDBCSLeadByte implementation

* Address PR comments

dll/vcruntime.cpp

@@ -0,0 +1,31 @@
+#include "common.h"
+
+namespace vcruntime {
+
+void *WIN_ENTRY memcpy(void *dest, const void *src, size_t count) { return ::memcpy(dest, src, count); }
+
+void *WIN_ENTRY memset(void *dest, int ch, size_t count) { return ::memset(dest, ch, count); }
+
+int WIN_ENTRY memcmp(const void *buf1, const void *buf2, size_t count) { return ::memcmp(buf1, buf2, count); }
+
+} // namespace vcruntime
+
+static void *resolveByName(const char *name) {
+	if (strcmp(name, "memcpy") == 0)
+		return (void *)vcruntime::memcpy;
+	if (strcmp(name, "memset") == 0)
+		return (void *)vcruntime::memset;
+	if (strcmp(name, "memcmp") == 0)
+		return (void *)vcruntime::memcmp;
+	return nullptr;
+}
+
+wibo::Module lib_vcruntime = {
+	(const char *[]){
+		"vcruntime140",
+		"vcruntime140.dll",
+		nullptr,
+	},
+	resolveByName,
+	nullptr,
+};