Subdirs: Initialize from parent before configuring.

Add new API for the subdirs command to cmState.

This fixes a regression introduced in commit f716460e (cmMakefile: Move
invokation to initialize snapshot., 2015-10-06).

Source/cmMakefile.cxx

@@ -1647,6 +1647,7 @@ void cmMakefile::Configure()
   std::vector<cmMakefile*>::iterator sdi = subdirs.begin();
   for (; sdi != subdirs.end(); ++sdi)
     {
+    (*sdi)->StateSnapshot.InitializeFromParent_ForSubdirsCommand();
     this->ConfigureSubDirectory(*sdi);
     }
 

Source/cmState.cxx

@@ -1447,6 +1447,20 @@ std::string cmState::Snapshot::GetProjectName() const
   return this->Position->BuildSystemDirectory->ProjectName;
 }
 
+void cmState::Snapshot::InitializeFromParent_ForSubdirsCommand()
+{
+  std::string currentSrcDir = this->GetDefinition("CMAKE_CURRENT_SOURCE_DIR");
+  std::string currentBinDir = this->GetDefinition("CMAKE_CURRENT_BINARY_DIR");
+  this->InitializeFromParent();
+  this->SetDefinition("CMAKE_SOURCE_DIR",
+                      this->State->GetSourceDirectory());
+  this->SetDefinition("CMAKE_BINARY_DIR",
+                      this->State->GetBinaryDirectory());
+
+  this->SetDefinition("CMAKE_CURRENT_SOURCE_DIR", currentSrcDir.c_str());
+  this->SetDefinition("CMAKE_CURRENT_BINARY_DIR", currentBinDir.c_str());
+}
+
 cmState::Directory::Directory(
     cmLinkedTree<BuildsystemDirectoryStateType>::iterator iter,
     const cmState::Snapshot& snapshot)

Source/cmState.h

@@ -90,6 +90,8 @@ public:
     void SetProjectName(std::string const& name);
     std::string GetProjectName() const;
 
+    void InitializeFromParent_ForSubdirsCommand();
+
     struct StrictWeakOrder
     {
       bool operator()(const cmState::Snapshot& lhs,

Tests/SubDir/CMakeLists.txt

@@ -1,6 +1,10 @@
 cmake_minimum_required (VERSION 2.6)
 project(SUBDIR)
+
 subdirs(Executable EXCLUDE_FROM_ALL Examples)
+
+set(DEFINED_AFTER_SUBDIRS_COMMAND 42)
+
 write_file(${SUBDIR_BINARY_DIR}/ShouldBeHere "This file should exist.")
 #WATCOM WMAKE does not support + in the name of a file!
 if(WATCOM)

Tests/SubDir/Executable/CMakeLists.txt

@@ -1 +1,13 @@
 add_executable(test test.cxx)
+
+if (NOT DEFINED_AFTER_SUBDIRS_COMMAND)
+  message(FATAL_ERROR "DEFINED_AFTER_SUBDIRS_COMMAND should be defined.")
+endif()
+
+string(FIND "${CMAKE_CURRENT_BINARY_DIR}" "SubDir/Executable" location)
+string(LENGTH "${CMAKE_CURRENT_BINARY_DIR}" dirLength)
+math(EXPR suffixLength "${dirLength} - ${location}")
+
+if (NOT suffixLength EQUAL 17)
+  message(FATAL_ERROR "CMAKE_CURRENT_BINARY_DIR does not end with \"SubDir/Executable\"")
+endif()