Introduce target property <LANG>_VISIBILITY_PRESET

This is initialized by CMAKE_<LANG>_VISIBILITY_PRESET. The target
property is used as the operand to the -fvisibility= compile option
with GNU compilers and clang.

Tests/Module/GenerateExportHeader/CMakeLists.txt

@@ -141,6 +141,8 @@ endmacro()
 
 include(GenerateExportHeader)
 
+add_subdirectory(visibility_preset)
+
 add_compiler_export_flags()
 
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})

Tests/Module/GenerateExportHeader/visibility_preset/CMakeLists.txt

@@ -0,0 +1,13 @@
+
+set(CMAKE_CXX_VISIBILITY_PRESET hidden)
+
+if (CMAKE_CXX_FLAGS MATCHES "-fvisibility=hidden")
+  message(SEND_ERROR "Do not use add_compiler_export_flags before adding this directory")
+endif()
+
+add_library(visibility_preset SHARED visibility_preset.cpp)
+generate_export_header(visibility_preset)
+
+add_executable(visibility_preset_exe main.cpp)
+
+target_link_libraries(visibility_preset_exe visibility_preset)

Tests/Module/GenerateExportHeader/visibility_preset/main.cpp

@@ -0,0 +1,9 @@
+
+#include "visibility_preset.h"
+
+int main()
+{
+  VisibilityPreset vp;
+  vp.someMethod();
+  return 0;
+}

Tests/Module/GenerateExportHeader/visibility_preset/visibility_preset.cpp

@@ -0,0 +1,7 @@
+
+#include "visibility_preset.h"
+
+void VisibilityPreset::someMethod()
+{
+
+}

Tests/Module/GenerateExportHeader/visibility_preset/visibility_preset.h

@@ -0,0 +1,13 @@
+
+#ifndef VISIBILITY_PRESET_H
+#define VISIBILITY_PRESET_H
+
+#include "visibility_preset_export.h"
+
+class VISIBILITY_PRESET_EXPORT VisibilityPreset
+{
+public:
+  void someMethod();
+};
+
+#endif