BUG: Remove implicit include dir suppression

We used to suppress generation of -I/usr/include (and on OSX also
-I/usr/local/include).  This behavior seems to cause more trouble than
it's worth, so I'm removing it until someone encounters the original
problem it fixed.  See issue #8598.

Modules/Platform/Darwin-icc.cmake

@@ -103,7 +103,6 @@ SET(CMAKE_Fortran_CREATE_SHARED_MODULE
 #  We can use $ENV{INTEL_LICENSE_FILE} to try and get at the installation location for ICC. 
 # We also need to consider to use cce (which is the 64bit compiler) and not JUST the 32bit compiler.
 # I have no idea what the best way to do that would be.
-SET(CMAKE_PLATFORM_IMPLICIT_INCLUDE_DIRECTORIES /usr/local/include )
 
 
 # default to searching for frameworks first

Modules/Platform/Darwin.cmake

@@ -217,7 +217,6 @@ SET(CMAKE_CXX_CREATE_MACOSX_FRAMEWORK
 
 
  
-SET(CMAKE_PLATFORM_IMPLICIT_INCLUDE_DIRECTORIES /usr/local/include)
 # default to searching for frameworks first
 SET(CMAKE_FIND_FRAMEWORK FIRST)
 # set up the default search directories for frameworks

Source/cmLocalGenerator.cxx

@@ -1293,8 +1293,7 @@ const char* cmLocalGenerator::GetIncludeFlags(const char* lang)
 }
 
 //----------------------------------------------------------------------------
-void cmLocalGenerator::GetIncludeDirectories(std::vector<std::string>& dirs,
-                                             bool filter_system_dirs)
+void cmLocalGenerator::GetIncludeDirectories(std::vector<std::string>& dirs)
 {
   // Need to decide whether to automatically include the source and
   // binary directories at the beginning of the include path.
@@ -1360,24 +1359,6 @@ void cmLocalGenerator::GetIncludeDirectories(std::vector<std::string>& dirs,
       }
     }
 
-  if(filter_system_dirs)
-    {
-    // Do not explicitly add the standard include path "/usr/include".
-    // This can cause problems with certain standard library
-    // implementations because the wrong headers may be found first.
-    emitted.insert("/usr/include");
-    if(const char* implicitIncludes = this->Makefile->GetDefinition
-       ("CMAKE_PLATFORM_IMPLICIT_INCLUDE_DIRECTORIES"))
-      {
-      std::vector<std::string> implicitIncludeVec;
-      cmSystemTools::ExpandListArgument(implicitIncludes, implicitIncludeVec);
-      for(unsigned int k = 0; k < implicitIncludeVec.size(); ++k)
-        {
-        emitted.insert(implicitIncludeVec[k]);
-        }
-      }
-    }
-
   // Get the project-specified include directories.
   std::vector<std::string>& includes = 
     this->Makefile->GetIncludeDirectories();

Source/cmLocalGenerator.h

@@ -189,8 +189,7 @@ public:
     { return true; }
 
   /** Get the include flags for the current makefile and language.  */
-  void GetIncludeDirectories(std::vector<std::string>& dirs,
-                             bool filter_system_dirs = true);
+  void GetIncludeDirectories(std::vector<std::string>& dirs);
 
   /** Compute the language used to compile the given source file.  */
   const char* GetSourceFileLanguage(const cmSourceFile& source);

Source/cmLocalUnixMakefileGenerator3.cxx

@@ -500,7 +500,7 @@ void cmLocalUnixMakefileGenerator3::WriteDirectoryInformationFile()
   infoFileStream
     << "SET(CMAKE_C_INCLUDE_PATH\n";
   std::vector<std::string> includeDirs;
-  this->GetIncludeDirectories(includeDirs, false);
+  this->GetIncludeDirectories(includeDirs);
   for(std::vector<std::string>::iterator i = includeDirs.begin();
       i != includeDirs.end(); ++i)
     {