include_directories: Fix handling of empty or space-only entries

This is a regression introduced in commit 0d46e9a0 (Store includes
from the same include_directories call together., 2013-01-20).

Reported at

 http://thread.gmane.org/gmane.comp.programming.tools.cmake.user/46695/focus=7847

1 files changed, 13 insertions, 2 deletions

diff --git a/Source/cmIncludeDirectoryCommand.cxx b/Source/cmIncludeDirectoryCommand.cxx
index ffb0e80..30c1743 100644
--- a/Source/cmIncludeDirectoryCommand.cxx
+++ b/Source/cmIncludeDirectoryCommand.cxx
@@ -116,13 +116,19 @@ void cmIncludeDirectoryCommand::GetIncludes(const std::string &arg,
       {
       std::string inc = arg.substr(lastPos,pos);
       this->NormalizeInclude(inc);
-      incs.push_back(inc);
+      if (!inc.empty())
+        {
+        incs.push_back(inc);
+        }
       }
     lastPos = pos + 1;
     }
   std::string inc = arg.substr(lastPos);
   this->NormalizeInclude(inc);
-  incs.push_back(inc);
+  if (!inc.empty())
+    {
+    incs.push_back(inc);
+    }
 }
 
 void cmIncludeDirectoryCommand::NormalizeInclude(std::string &inc)
@@ -133,6 +139,11 @@ void cmIncludeDirectoryCommand::NormalizeInclude(std::string &inc)
     {
     inc.assign(inc, b, 1+e-b);   // copy the remaining substring
     }
+  else
+    {
+    inc = "";
+    return;
+    }
 
   if (!cmSystemTools::IsOff(inc.c_str()))
     {