Move similar/main/config.c -> similar/main/config.cpp

SConstruct

@@ -754,7 +754,7 @@ class DXXProgram(DXXCommon):
 'main/aipath.cpp',
 'main/automap.cpp',
 'main/cntrlcen.cpp',
-'main/config.c',
+'main/config.cpp',
 'main/console.c',
 'main/controls.c',
 'main/credits.c',

common/main/config.h

@@ -24,6 +24,10 @@ COPYRIGHT 1993-1999 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
 #include "player.h"
 #include "mission.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct Cfg
 {
 	ubyte DigiVolume;
@@ -65,4 +69,8 @@ extern struct Cfg GameCfg;
 extern int ReadConfigFile(void);
 extern int WriteConfigFile(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif