diff --git a/SConstruct b/SConstruct
index 87328ba18..085cfe1b7 100644
--- a/SConstruct
+++ b/SConstruct
@@ -776,7 +776,7 @@ class DXXProgram(DXXCommon):
 'main/kmatrix.cpp',
 'main/laser.cpp',
 'main/lighting.cpp',
-'main/menu.c',
+'main/menu.cpp',
 'main/mglobal.c',
 'main/mission.c',
 'main/morph.c',
diff --git a/common/main/net_udp.h b/common/main/net_udp.h
index 3d65aafd7..4ab927b07 100644
--- a/common/main/net_udp.h
+++ b/common/main/net_udp.h
@@ -4,8 +4,13 @@
  *
  */
 
+#pragma once
 #include "multi.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // Exported functions
 int net_udp_setup_game(void);
 void net_udp_manual_join_game();
@@ -155,4 +160,7 @@ typedef struct UDP_mdata_recv
 	int				pkt_num[UDP_MDATA_STOR_QUEUE_SIZE];
 	int				cur_slot; // index we can use for a new pkt_num
 } __pack__ UDP_mdata_recv;
-	
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/similar/main/menu.c b/similar/main/menu.cpp
similarity index 99%
rename from similar/main/menu.c
rename to similar/main/menu.cpp
index afd13196a..c69b82e13 100644
--- a/similar/main/menu.c
+++ b/similar/main/menu.cpp
@@ -1330,7 +1330,7 @@ typedef struct browser
 
 void list_dir_el(browser *b, const char *origdir, const char *fname)
 {
-	char *ext;
+	const char *ext;
 	const char *const *i = NULL;
 	
 	ext = strrchr(fname, '.');