Indentations and GCC attribute added

CMakeLists.txt

@@ -102,6 +102,6 @@ if(BUILD_DOCUMENTATION)
 		install(DIRECTORY  ${CMAKE_CURRENT_SOURCE_DIR}/doc/html/ TYPE DOC)
 endif()
 
-if(MSVC AND BUILD_SHARED_LIBS)
+if(BUILD_SHARED_LIBS)
     add_definitions(-DTGBOT_DLL)
 endif()

include/tgbot/export.h

@@ -2,19 +2,27 @@
 #define TGBOT_EXPORT_H
 
 #ifndef TGBOT_API
-#ifdef _MSC_VER
-#ifdef TGBOT_DLL
-#ifdef TgBot_EXPORTS
-#define TGBOT_API __declspec(dllexport)
-#else
-#define TGBOT_API __declspec(dllimport)
-#endif
-#else
-#define TGBOT_API
-#endif
-#else
-#define TGBOT_API
-#endif
+    #ifdef TGBOT_DLL
+        #if defined _WIN32 || defined __CYGWIN__
+            #define TGBOT_HELPER_DLL_IMPORT __declspec(dllimport)
+            #define TGBOT_HELPER_DLL_EXPORT __declspec(dllexport)
+        #else
+            #if __GNUC__ >= 4
+                #define TGBOT_HELPER_DLL_IMPORT __attribute__ ((visibility ("default")))
+                #define TGBOT_HELPER_DLL_EXPORT __attribute__ ((visibility ("default")))
+            #else
+                #define TGBOT_HELPER_DLL_IMPORT
+                #define TGBOT_HELPER_DLL_EXPORT
+            #endif
+        #endif
+        #ifdef TgBot_EXPORTS
+            #define TGBOT_API TGBOT_HELPER_DLL_EXPORT
+        #else
+            #define FOX_API TGBOT_HELPER_DLL_IMPORT
+        #endif
+    #else
+        #define TGBOT_API
+    #endif
 #endif
 
 #endif //TGBOT_EXPORT_H