Use explicit symbol visibility control in GCC/clang

dtool/src/dtoolbase/dtoolbase.h

@@ -431,6 +431,9 @@
 #if defined(WIN32_VC) && !defined(CPPPARSER) && !defined(LINK_ALL_STATIC)
 #define EXPORT_CLASS __declspec(dllexport)
 #define IMPORT_CLASS __declspec(dllimport)
+#elif __GNUC__ >= 4 && !defined(CPPPARSER) && !defined(LINK_ALL_STATIC)
+#define EXPORT_CLASS __attribute__((visibility("default")))
+#define IMPORT_CLASS
 #else
 #define EXPORT_CLASS
 #define IMPORT_CLASS

dtool/src/dtoolbase/dtoolsymbols.h

@@ -97,7 +97,12 @@
 /* These two are always defined empty, because pystub is statically
    built.  But we leave the symbol around in case we change our minds
    to make pystub once again be a dynamic library. */
+#if __GNUC__ >= 4
+/* In GCC, though, we still need to mark the symbols as visible. */
+#define EXPCL_PYSTUB __attribute__((visibility("default")))
+#else
 #define EXPCL_PYSTUB
+#endif
 #define EXPTP_PYSTUB
 
 #endif

dtool/src/interrogate/interrogate_module.cxx

@@ -135,6 +135,8 @@ int write_python_table_native(ostream &out) {
       << "\n"
       << "#ifdef _WIN32\n"
       << "extern \"C\" __declspec(dllexport) PyObject *PyInit_" << library_name << "();\n"
+      << "#elif __GNUC__ >= 4\n"
+      << "extern \"C\" __attribute__((visibility(\"default\"))) PyObject *PyInit_" << library_name << "();\n"
       << "#else\n"
       << "extern \"C\" PyObject *PyInit_" << library_name << "();\n"
       << "#endif\n"
@@ -180,6 +182,8 @@ int write_python_table_native(ostream &out) {
       << "\n"
       << "#ifdef _WIN32\n"
       << "extern \"C\" __declspec(dllexport) void init" << library_name << "();\n"
+      << "#elif __GNUC__ >= 4\n"
+      << "extern \"C\" __attribute__((visibility(\"default\"))) void init" << library_name << "();\n"
       << "#else\n"
       << "extern \"C\" void init" << library_name << "();\n"
       << "#endif\n"

dtool/src/prc/notifyCategoryProxy.h

@@ -125,8 +125,9 @@ INLINE ostream &operator << (ostream &out, NotifyCategoryProxy<GetCategory> &pro
 // appear in the config_*.h file.  The proxy object will be named
 // basename_cat.
 
-#if defined(WIN32_VC) && !defined(CPPPARSER)
-
+#ifdef CPPPARSER
+#define NotifyCategoryDecl(basename, expcl, exptp)
+#else
 #define NotifyCategoryDecl(basename, expcl, exptp) \
   class expcl NotifyCategoryGetCategory_ ## basename { \
   public: \
@@ -135,18 +136,7 @@ INLINE ostream &operator << (ostream &out, NotifyCategoryProxy<GetCategory> &pro
   }; \
   exptp template class expcl NotifyCategoryProxy<NotifyCategoryGetCategory_ ## basename>; \
   extern expcl NotifyCategoryProxy<NotifyCategoryGetCategory_ ## basename> basename ## _cat;
-
-#else // WIN32_VC
-
-#define NotifyCategoryDecl(basename, expcl, exptp) \
-  class NotifyCategoryGetCategory_ ## basename { \
-  public: \
-    NotifyCategoryGetCategory_ ## basename(); \
-    static NotifyCategory *get_category(); \
-  }; \
-  extern NotifyCategoryProxy<NotifyCategoryGetCategory_ ## basename> basename ## _cat;
-
-#endif  // WIN32_VC
+#endif
 
 // This macro is the same as the above, except that it declares a category
 // that is not intended to be exported from any DLL.

makepanda/makepanda.py

@@ -1160,6 +1160,8 @@ def CompileCxx(obj,src,opts):
             if (opt=="ALWAYS") or (opt in opts): cmd += ' -D' + var + '=' + val
         for x in ipath: cmd += ' -I' + x
 
+        cmd += ' -fvisibility=hidden'
+
         # Mac-specific flags.
         if GetTarget() == "darwin":
             cmd += " -Wno-deprecated-declarations"