Merging changes from AeroXuk/libpostal_windows.

src/strndup.c

@@ -0,0 +1,16 @@
+#ifndef HAVE_STRNDUP
+
+#include <stdlib.h>
+#include <string.h>
+
+char *strndup(const char *s, size_t n)
+{
+    char* new = malloc(n+1);
+    if (new) {
+        strncpy(new, s, n);
+        new[n] = '\0';
+    }
+    return new;
+}
+
+#endif /* HAVE_STRNDUP */