[cmake] fix CheckAndSetFlag

Actually add the flags provided and not discard them.

cmake/CheckAndSetFlag.cmake

@@ -1,28 +1,31 @@
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
 
+macro(RemoveFlag FLAG)
+  string(REPLACE "${FLAG}" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
+  string(REPLACE "${FLAG}" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+endmacro()
+
 macro(CheckAndSetFlag FLAG)
-  if(FLAG)
+  get_property(languages GLOBAL PROPERTY ENABLED_LANGUAGES)
-    get_property(languages GLOBAL PROPERTY ENABLED_LANGUAGES)
 
-    unset(C_FLAG)
+  unset(C_FLAG)
-    unset(CXX_FLAG)
+  unset(CXX_FLAG)
-    if("C" IN_LIST languages)
+  if("C" IN_LIST languages)
-      check_c_compiler_flag("${FLAG}" C_FLAG)
+    check_c_compiler_flag("${FLAG}" C_FLAG)
-      if(C_FLAG)
+    if(C_FLAG)
-        string(APPEND CMAKE_C_FLAGS " ${FLAG}")
+      string(APPEND CMAKE_C_FLAGS " ${FLAG}")
-      endif()
-    endif()
-
-    if("CXX" IN_LIST languages)
-      check_cxx_compiler_flag("${FLAG}" CXX_FLAG)
-      if(CXX_FLAG)
-        string(APPEND CMAKE_CXX_FLAGS " ${FLAG}")
-      endif()
-    endif()
-
-    if(NOT C_FLAG AND NOT CXX_FLAG)
-      message(WARNING "compiler does not support ${FLAG}")
     endif()
   endif()
+
+  if("CXX" IN_LIST languages)
+    check_cxx_compiler_flag("${FLAG}" CXX_FLAG)
+    if(CXX_FLAG)
+      string(APPEND CMAKE_CXX_FLAGS " ${FLAG}")
+    endif()
+  endif()
+
+  if(NOT C_FLAG AND NOT CXX_FLAG)
+    message(WARNING "compiler does not support ${FLAG}")
+  endif()
 endmacro()

cmake/ExportAllSymbols.cmake

@@ -4,8 +4,8 @@ option(EXPORT_ALL_SYMBOLS "Export all symbols form library" OFF)
 
 if(EXPORT_ALL_SYMBOLS)
   add_compile_definitions(EXPORT_ALL_SYMBOLS)
+  removeflag(-fvisibility=hidden)
 else()
   message(STATUS "${} default symbol visibility: hidden")
-
   checkandsetflag(-fvisibility=hidden)
 endif()