diff --git a/src/boards/mmc3.h b/src/boards/mmc3.h
index 3dc1e47..6a30fce 100644
--- a/src/boards/mmc3.h
+++ b/src/boards/mmc3.h
@@ -1,3 +1,6 @@
+#ifndef _MMC3_H
+#define _MMC3_H
+
 extern uint8 MMC3_cmd;
 extern uint8 mmc3opts;
 extern uint8 A000B;
@@ -24,3 +27,5 @@ DECLFW(MMC3_CMDWrite);
 DECLFW(MMC3_IRQWrite);
 
 void GenMMC3_Init(CartInfo *info, int prg, int chr, int wram, int battery);
+
+#endif /* _MMC3_H */
diff --git a/src/input/share.h b/src/input/share.h
index 11ad59c..a5e1e4b 100644
--- a/src/input/share.h
+++ b/src/input/share.h
@@ -1,3 +1,6 @@
+#ifndef _SHARE_H
+#define _SHARE_H
+
 #include "../fceu-types.h"
 #include "../input.h"
 #include "../fceu.h"
@@ -9,3 +12,5 @@
 void FCEUMOV_AddJoy(uint8 *js);
 void FCEU_DrawCursor(uint8 *buf, int xc, int yc);
 void FCEU_DrawGunSight(uint8 *buf, int xc, int yc);
+
+#endif /* _SHARE_H */