Factor old-style -D flags out from -I flag generation

Move the GetDefineFlags call from cmLocalGenerator::GetIncludeFlags to
all call sites so that the method exclusively constructs a string of
include search path flags.

Source/cmLocalGenerator.cxx

@@ -575,6 +575,7 @@ void cmLocalGenerator::AddCustomCommandToCreateObject(const char* ofname,
   flags += this->Makefile->GetSafeDefinition(varString.c_str());
   flags += " ";
   flags += this->GetIncludeFlags(lang);
+  flags += this->Makefile->GetDefineFlags();
 
   // Construct the command lines.
   cmCustomCommandLines commandLines;
@@ -1291,8 +1292,6 @@ const char* cmLocalGenerator::GetIncludeFlags(const char* lang)
     {
     flags[flags.size()-1] = ' ';
     }
-  std::string defineFlags = this->Makefile->GetDefineFlags();
-  flags += defineFlags;
   this->LanguageToIncludeFlags[lang] = flags;
 
   // Use this temorary variable for the return value to work-around a

Source/cmMakefileTargetGenerator.cxx

@@ -312,6 +312,11 @@ void cmMakefileTargetGenerator::WriteTargetLanguageFlags()
     // Add include directory flags.
     this->LocalGenerator->
       AppendFlags(flags, this->LocalGenerator->GetIncludeFlags(lang));
+
+    // Append old-style preprocessor definition flags.
+    this->LocalGenerator->
+      AppendFlags(flags, this->Makefile->GetDefineFlags());
+
     // Add include directory flags.
     this->LocalGenerator->
       AppendFlags(flags,this->GetFrameworkFlags().c_str());