ENH: add support for removing language flags from shared library and shared module link commands

Modules/Platform/Darwin.cmake

@@ -24,6 +24,8 @@ IF(NOT XCODE)
   SET(CMAKE_SHARED_LIBRARY_SONAME_CXX_FLAG "-install_name")
 ENDIF(NOT XCODE)
 
+SET(CMAKE_C_CREATE_SHARED_LIBRARY_FORBIDDEN_FLAGS -w)
+SET(CMAKE_CXX_CREATE_SHARED_LIBRARY_FORBIDDEN_FLAGS -w)
 SET(CMAKE_C_CREATE_SHARED_LIBRARY
   "<CMAKE_C_COMPILER> <LANGUAGE_COMPILE_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS> <LINK_FLAGS> -o <TARGET> -install_name <TARGET_INSTALLNAME_DIR><TARGET_SONAME> <OBJECTS> <LINK_LIBRARIES>")
 SET(CMAKE_CXX_CREATE_SHARED_LIBRARY

Source/cmMakefileLibraryTargetGenerator.cxx

@@ -246,16 +246,23 @@ void cmMakefileLibraryTargetGenerator::WriteLibraryRules
   // Add the link message.
   std::string buildEcho = "Linking ";
   buildEcho += linkLanguage;
+  const char* forbiddenFlagVar = 0;
   switch(this->Target->GetType())
     {
     case cmTarget::STATIC_LIBRARY:
-      buildEcho += " static library "; break;
+      buildEcho += " static library "; 
+      break;
     case cmTarget::SHARED_LIBRARY:
-      buildEcho += " shared library "; break;
+      forbiddenFlagVar = "_CREATE_SHARED_LIBRARY_FORBIDDEN_FLAGS";
+      buildEcho += " shared library ";
+      break;
     case cmTarget::MODULE_LIBRARY:
-      buildEcho += " shared module "; break;
+      forbiddenFlagVar = "_CREATE_SHARED_MODULE_FORBIDDEN_FLAGS";
+      buildEcho += " shared module ";
+      break;
     default:
-      buildEcho += " library "; break;
+      buildEcho += " library "; 
+      break;
     }
   buildEcho += targetOutPath.c_str();
   this->LocalGenerator->AppendEcho(commands, buildEcho.c_str());
@@ -436,6 +443,13 @@ void cmMakefileLibraryTargetGenerator::WriteLibraryRules
   this->LocalGenerator
     ->AddLanguageFlags(langFlags, linkLanguage,
                        this->LocalGenerator->m_ConfigurationName.c_str());
+  // remove any language flags that might not work with the
+  // particular os
+  if(forbiddenFlagVar)
+    {
+    this->RemoveForbiddenFlags(forbiddenFlagVar,
+                               linkLanguage, langFlags);
+    }
   vars.LanguageCompileFlags = langFlags.c_str();
   // Expand placeholders in the commands.
   this->LocalGenerator->m_TargetImplib = targetOutPathImport;

Source/cmMakefileTargetGenerator.cxx

@@ -799,3 +799,25 @@ void cmMakefileTargetGenerator
   delete this->InfoFileStream;
   delete this->FlagFileStream;
 }
+
+void cmMakefileTargetGenerator::RemoveForbiddenFlags(const char* flagVar,
+                                                     const char* linkLang, 
+                                                     std::string& linkFlags)
+{
+  // check for language flags that are not allowed at link time, and
+  // remove them, -w on darwin for gcc -w -dynamiclib sends -w to libtool
+  // which fails, there may be more]
+  
+  std::string removeFlags = "CMAKE_";
+  removeFlags += linkLang;
+  removeFlags += flagVar;
+  std::string removeflags = 
+    this->Makefile->GetSafeDefinition(removeFlags.c_str());
+  std::vector<std::string> removeList;
+  cmSystemTools::ExpandListArgument(removeflags, removeList);
+  for(std::vector<std::string>::iterator i = removeList.begin();
+      i != removeList.end(); ++i)
+    {
+    cmSystemTools::ReplaceString(linkFlags, i->c_str(), "");
+    }
+}

Source/cmMakefileTargetGenerator.h

@@ -99,7 +99,8 @@ protected:
   void AppendTargetDepends(std::vector<std::string>& depends);
 
   virtual void CloseFileStreams();
-  
+  void RemoveForbiddenFlags(const char* flagVar, const char* linkLang, 
+                            std::string& linkFlags);
   cmStdString TargetName;
   cmTarget *Target;
   cmLocalUnixMakefileGenerator3 *LocalGenerator;