Add #ifdef __cplusplus extern "C" {} wrappers to .h files

libgnucash/engine/cap-gains.h

@@ -82,6 +82,10 @@ ToDo:
 
 #include "gnc-engine.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /** The xaccSplitGetCapGains() method returns the value of
  *    capital gains (if any) associated with the indicated
  *    split. In order for there to be any capital gains,
@@ -205,6 +209,10 @@ Split * xaccSplitAssignToLot (Split *split, GNCLot *lot);
 void xaccSplitComputeCapGains(Split *split, Account *gain_acc);
 void xaccLotComputeCapGains (GNCLot *lot, Account *gain_acc);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* XACC_CAP_GAINS_H */
 /** @} */
 /** @} */

libgnucash/engine/gnc-lot-p.h

@@ -37,9 +37,17 @@
 #ifndef GNC_LOT_P_H
 #define GNC_LOT_P_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define gnc_lot_set_guid(L,G)  qof_instance_set_guid(QOF_INSTANCE(L),&(G))
 
 /* Register with the Query engine */
 gboolean gnc_lot_register (void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GNC_LOT_P_H */