Hide visibility of classes to avoid symbol clashes

src/pmacAsynIPPort.h

@@ -25,8 +25,7 @@ extern "C" {
  * 172.23.243.156:1025)
  * @return status
  */
-epicsShareFunc int pmacAsynIPPortConfigure(const char *portName,
-                                           const char *hostInfo);
+int HIDDEN pmacAsynIPPortConfigure(const char *portName, const char *hostInfo);
 
 #ifdef __cplusplus
 }

src/turboPmacAxis.h

@@ -4,9 +4,9 @@
 #include "turboPmacController.h"
 #include <memory>
 
-struct turboPmacAxisImpl;
+struct HIDDEN turboPmacAxisImpl;
 
-class turboPmacAxis : public sinqAxis {
+class HIDDEN turboPmacAxis : public sinqAxis {
   public:
     /**
      * @brief Construct a new turboPmacAxis

src/turboPmacController.h

@@ -15,11 +15,11 @@
 // Forward declaration of the controller class to resolve the cyclic dependency
 // between the controller and the axis .h-file. See
 // https://en.cppreference.com/w/cpp/language/class.
-class turboPmacAxis;
+class HIDDEN turboPmacAxis;
 
-struct turboPmacControllerImpl;
+struct HIDDEN turboPmacControllerImpl;
 
-class turboPmacController : public sinqController {
+class HIDDEN turboPmacController : public sinqController {
   public:
     /**
      * @brief Construct a new turboPmacController object. This function is meant