Honor LINK_WHAT_YOU_USE when set to OFF

Explicitly setting variable CMAKE_LINK_WHAT_YOU_USE or property
LINK_WHAT_YOU_USE to OFF should not cause LWYU to run.  Fix the
property lookup to use GetPropertyAsBool.

Source/cmMakefileExecutableTargetGenerator.cxx

@@ -192,7 +192,7 @@ void cmMakefileExecutableTargetGenerator::WriteExecutableRule(bool relink)
     this->LocalGenerator->AppendFlags(
       linkFlags, this->Makefile->GetDefinition(export_flag_var));
   }
-  if (this->GeneratorTarget->GetProperty("LINK_WHAT_YOU_USE")) {
+  if (this->GeneratorTarget->GetPropertyAsBool("LINK_WHAT_YOU_USE")) {
     this->LocalGenerator->AppendFlags(linkFlags, " -Wl,--no-as-needed");
   }
 
@@ -354,7 +354,7 @@ void cmMakefileExecutableTargetGenerator::WriteExecutableRule(bool relink)
     vars.LinkFlags = linkFlags.c_str();
     vars.Manifests = manifests.c_str();
 
-    if (this->GeneratorTarget->GetProperty("LINK_WHAT_YOU_USE")) {
+    if (this->GeneratorTarget->GetPropertyAsBool("LINK_WHAT_YOU_USE")) {
       std::string cmakeCommand = this->LocalGenerator->ConvertToOutputFormat(
         cmSystemTools::GetCMakeCommand(), cmLocalGenerator::SHELL);
       cmakeCommand += " -E __run_iwyu --lwyu=";

Source/cmMakefileLibraryTargetGenerator.cxx

@@ -161,7 +161,7 @@ void cmMakefileLibraryTargetGenerator::WriteSharedLibraryRules(bool relink)
     extraFlags, "CMAKE_SHARED_LINKER_FLAGS", this->ConfigName);
   this->AddModuleDefinitionFlag(extraFlags);
 
-  if (this->GeneratorTarget->GetProperty("LINK_WHAT_YOU_USE")) {
+  if (this->GeneratorTarget->GetPropertyAsBool("LINK_WHAT_YOU_USE")) {
     this->LocalGenerator->AppendFlags(extraFlags, " -Wl,--no-as-needed");
   }
   this->WriteLibraryRules(linkRuleVar, extraFlags, relink);
@@ -638,7 +638,7 @@ void cmMakefileLibraryTargetGenerator::WriteLibraryRules(
       // Get the set of commands.
       std::string linkRule = this->GetLinkRule(linkRuleVar);
       cmSystemTools::ExpandListArgument(linkRule, real_link_commands);
-      if (this->GeneratorTarget->GetProperty("LINK_WHAT_YOU_USE") &&
+      if (this->GeneratorTarget->GetPropertyAsBool("LINK_WHAT_YOU_USE") &&
           (this->GeneratorTarget->GetType() == cmState::SHARED_LIBRARY)) {
         std::string cmakeCommand = this->LocalGenerator->ConvertToOutputFormat(
           cmSystemTools::GetCMakeCommand(), cmLocalGenerator::SHELL);

Source/cmNinjaNormalTargetGenerator.cxx

@@ -315,7 +315,7 @@ std::vector<std::string> cmNinjaNormalTargetGenerator::ComputeLinkCmd()
     const char* linkCmd = mf->GetDefinition(linkCmdVar);
     if (linkCmd) {
       cmSystemTools::ExpandListArgument(linkCmd, linkCmds);
-      if (this->GetGeneratorTarget()->GetProperty("LINK_WHAT_YOU_USE")) {
+      if (this->GetGeneratorTarget()->GetPropertyAsBool("LINK_WHAT_YOU_USE")) {
         std::string cmakeCommand =
           this->GetLocalGenerator()->ConvertToOutputFormat(
             cmSystemTools::GetCMakeCommand(), cmLocalGenerator::SHELL);
@@ -505,7 +505,7 @@ void cmNinjaNormalTargetGenerator::WriteLinkStatement()
 
   vars["LINK_PATH"] = frameworkPath + linkPath;
   std::string lwyuFlags;
-  if (genTarget.GetProperty("LINK_WHAT_YOU_USE")) {
+  if (genTarget.GetPropertyAsBool("LINK_WHAT_YOU_USE")) {
     lwyuFlags = " -Wl,--no-as-needed";
   }