rename rng.c to random.c and rom4.c to overworld.c

include/random.h

@@ -0,0 +1,18 @@
+#ifndef GUARD_RANDOM_H
+#define GUARD_RANDOM_H
+
+extern u32 gRngValue;
+extern u32 gRng2Value;
+
+//Returns a 16-bit pseudorandom number
+u16 Random(void);
+u16 Random2(void);
+
+//Returns a 32-bit pseudorandom number
+#define Random32() (Random() | (Random() << 16))
+
+//Sets the initial seed value of the pseudorandom number generator
+void SeedRng(u16 seed);
+void SeedRng2(u16 seed);
+
+#endif // GUARD_RANDOM_H