ENH: merge changes from head to 26 branch

12 files changed, 324 insertions, 146 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 63ed5645c3..392829dc4a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -354,7 +354,7 @@ ENDMACRO (CMAKE_BUILD_UTILITIES)
 SET(CMake_VERSION_MAJOR 2)
 SET(CMake_VERSION_MINOR 6)
 SET(CMake_VERSION_PATCH 0)
-SET(CMake_VERSION_RC 51)
+SET(CMake_VERSION_RC 52)
 # CVS versions are odd, if this is an odd minor version
 # then set the CMake_VERSION_DATE variable
 IF("${CMake_VERSION_MINOR}" MATCHES "[13579]$")
diff --git a/ChangeLog.manual b/ChangeLog.manual
index 9d7295ccb6..b68ade35ea 100644
--- a/ChangeLog.manual
+++ b/ChangeLog.manual
@@ -15,6 +15,12 @@ Changes in CMake 2.6.0 RC 6
 - Fix some missing flags for vs IDE flag map
 - Fix MacOSX install symlink crash problem
 - Fix turning of Dev warnings with gui's
+- Fix backwards compatibility issue with FindMPI.cmake
+- Fix for bug 6605, add -L path for optimized in debug sometimes for
+  backwards compatibility
+- Allow for CMP0000 to be set before any warnings happen
+- Do not use FAT32 hack in VS 2005 and 2008 unless on a FAT32 disk,
+  causes try-compiles to be 3 times slower if FAT hack is present.
 
 Changes in CMake 2.6.0 
 
diff --git a/Modules/FindMPI.cmake b/Modules/FindMPI.cmake
index 627effce14..5e218e7074 100644
--- a/Modules/FindMPI.cmake
+++ b/Modules/FindMPI.cmake
@@ -1,95 +1,132 @@
-# This module looks for the Message Passing Interface (MPI).
+# - Message Passing Interface (MPI) module.
+# 
+# The Message Passing Interface (MPI) is a library used to write
+# high-performance parallel applications that use message passing, and
+# is typically deployed on a cluster. MPI is a standard interface
+# (defined by the MPI forum) for which many implementations are
+# available. All of these implementations have somewhat different
+# compilation approaches (different include paths, libraries to link
+# against, etc.), and this module tries to smooth out those differences.
 #
 # This module will set the following variables:
 #   MPI_FOUND                  TRUE if we have found MPI
 #   MPI_COMPILE_FLAGS          Compilation flags for MPI programs
-#   MPI_INCLUDE_PATH           Include path for MPI header
+#   MPI_INCLUDE_PATH           Include path(s) for MPI header
 #   MPI_LINK_FLAGS             Linking flags for MPI programs
-#   MPI_LIBRARIES              Libraries to link MPI programs against
-#   MPI_LIBRARY                Deprecated; first MPI library to link against
-#   MPI_EXTRA_LIBRARY          Deprecated; second MPI library to link against
+#   MPI_LIBRARY                First MPI library to link against (cached)
+#   MPI_EXTRA_LIBRARY          Extra MPI libraries to link against (cached)
+#   MPI_LIBRARIES              All libraries to link MPI programs against
 #   MPIEXEC                    Executable for running MPI programs
+#   MPIEXEC_NUMPROC_FLAG       Flag to pass to MPIEXEC before giving it the
+#                              number of processors to run on
+#   MPIEXEC_PREFLAGS           Flags to pass to MPIEXEC directly before the
+#                              executable to run.
+#   MPIEXEC_POSTFLAGS          Flags to pass to MPIEXEC after all other flags.
 #
 # This module will attempt to auto-detect these settings, first by
-# looking for a C++ MPI driver (e.g., mpic++, mpiCC, or mpicxx; set by
-# MPICXX) and later by checking common MPI paths and library names.
+# looking for a MPI compiler, which many MPI implementations provide
+# as a pass-through to the native compiler to simplify the compilation
+# of MPI programs. The MPI compiler is stored in the cache variable
+# MPI_COMPILER, and will attempt to look for commonly-named drivers
+# mpic++, mpicxx, mpiCC, or mpicc. If the compiler driver is found and
+# recognized, it will be used to set all of the module variables. To
+# skip this auto-detection, set MPI_LIBRARY and MPI_INCLUDE_PATH in
+# the CMake cache.
+#
+# If no compiler driver is found or the compiler driver is not
+# recognized, this module will then search for common include paths
+# and library names to try to detect MPI. 
+#
+# If CMake initially finds a different MPI than was intended, and you
+# want to use the MPI compiler auto-detection for a different MPI
+# implementation, set MPI_COMPILER to the MPI compiler driver you want
+# to use (e.g., mpicxx) and then set MPI_LIBRARY to the string
+# MPI_LIBRARY-NOTFOUND. When you re-configure, auto-detection of MPI
+# will run again with the newly-specified MPI_COMPILER.
+#
+# When using MPIEXEC to execute MPI applications, you should typically
+# use all of the MPIEXEC flags as follows:
+#   ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} PROCS ${MPIEXEC_PREFLAGS} EXECUTABLE
+#     ${MPIEXEC_POSTFLAGS} ARGS
+# where PROCS is the number of processors on which to execute the program,
+# EXECUTABLE is the MPI program, and ARGS are the arguments to pass to the 
+# MPI program.
 
 # Try to find the MPI driver program
-find_program(MPICXX 
-  NAMES mpic++ mpicxx mpiCC
-  DOC "MPI C++ compiler. Used only to detect MPI compilation flags.")
-mark_as_advanced(MPICXX)
+find_program(MPI_COMPILER 
+  NAMES mpic++ mpicxx mpiCC mpicc
+  DOC "MPI compiler. Used only to detect MPI compilation flags.")
+mark_as_advanced(MPI_COMPILER)
 
 find_program(MPIEXEC
-  NAMES mpiexec mpirun
+  NAMES mpiexec mpirun lamexec
   DOC "Executable for running MPI programs.")
-mark_as_advanced(MPIEXEC)
 
-if (NOT OLD_MPICXX STREQUAL MPICXX)
-  set(MPI_FORCE_RECONFIGURE TRUE)
-  set(OLD_MPICXX ${MPICXX} CACHE INTERNAL "Previous value of MPICXX" FORCE)
-endif (NOT OLD_MPICXX STREQUAL MPICXX)
-  
-if (NOT MPICXX)
-  # If there is no MPI C++ compiler, we force ourselves to configure
-  # MPI the old way.
-  set(MPI_FORCE_RECONFIGURE TRUE)
-endif (NOT MPICXX)
+set(MPIEXEC_NUMPROC_FLAG "-np" CACHE STRING "Flag used by MPI to specify the number of processes for MPIEXEC; the next option will be the number of processes.")
+set(MPIEXEC_PREFLAGS "" CACHE STRING "These flags will be directly before the executable that is being run by MPIEXEC.")
+set(MPIEXEC_POSTFLAGS "" CACHE STRING "These flags will come after all flags given to MPIEXEC.")
+set(MPIEXEC_MAX_NUMPROCS "2" CACHE STRING "Maximum number of processors available to run MPI applications.")
+mark_as_advanced(MPIEXEC MPIEXEC_NUMPROC_FLAG MPIEXEC_PREFLAGS 
+  MPIEXEC_POSTFLAGS MPIEXEC_MAX_NUMPROCS)
 
-if (MPICXX)
+if (MPI_INCLUDE_PATH AND MPI_LIBRARY)
+  # Do nothing: we already have MPI_INCLUDE_PATH and MPI_LIBRARY in
+  # the cache, and we don't want to override those settings.
+elseif (MPI_COMPILER)
   # Check whether the -showme:compile option works. This indicates
   # that we have either Open MPI or a newer version of LAM-MPI, and
   # implies that -showme:link will also work.
-  exec_program(${MPICXX} 
+  exec_program(${MPI_COMPILER} 
     ARGS -showme:compile 
     OUTPUT_VARIABLE MPI_COMPILE_CMDLINE
-    RETURN_VALUE MPICXX_RETURN)
+    RETURN_VALUE MPI_COMPILER_RETURN)
 
-  if (MPICXX_RETURN EQUAL 0)
+  if (MPI_COMPILER_RETURN EQUAL 0)
     # If we appear to have -showme:compile, then we should also have
     # -showme:link. Try it.
-    exec_program(${MPICXX} 
+    exec_program(${MPI_COMPILER} 
       ARGS -showme:link
       OUTPUT_VARIABLE MPI_LINK_CMDLINE
-      RETURN_VALUE MPICXX_RETURN)
-  endif (MPICXX_RETURN EQUAL 0)
+      RETURN_VALUE MPI_COMPILER_RETURN)
+  endif (MPI_COMPILER_RETURN EQUAL 0)
 
-  if (MPICXX_RETURN EQUAL 0)
+  if (MPI_COMPILER_RETURN EQUAL 0)
     # Do nothing: we have our command lines now
-  else (MPICXX_RETURN EQUAL 0)
+  else (MPI_COMPILER_RETURN EQUAL 0)
     # Older versions of LAM-MPI have "-showme". Try it.
-    exec_program(${MPICXX} 
+    exec_program(${MPI_COMPILER} 
       ARGS -showme
       OUTPUT_VARIABLE MPI_COMPILE_CMDLINE
-      RETURN_VALUE MPICXX_RETURN)
-  endif (MPICXX_RETURN EQUAL 0)  
+      RETURN_VALUE MPI_COMPILER_RETURN)
+  endif (MPI_COMPILER_RETURN EQUAL 0)  
 
-  if (MPICXX_RETURN EQUAL 0)
+  if (MPI_COMPILER_RETURN EQUAL 0)
     # Do nothing: we have our command lines now
-  else (MPICXX_RETURN EQUAL 0)
+  else (MPI_COMPILER_RETURN EQUAL 0)
     # MPICH uses "-show". Try it.
-    exec_program(${MPICXX} 
+    exec_program(${MPI_COMPILER} 
       ARGS -show
       OUTPUT_VARIABLE MPI_COMPILE_CMDLINE
-      RETURN_VALUE MPICXX_RETURN)
-  endif (MPICXX_RETURN EQUAL 0)  
+      RETURN_VALUE MPI_COMPILER_RETURN)
+  endif (MPI_COMPILER_RETURN EQUAL 0)  
 
-  if (MPICXX_RETURN EQUAL 0)
+  if (MPI_COMPILER_RETURN EQUAL 0)
     # We have our command lines, but we might need to copy
     # MPI_COMPILE_CMDLINE into MPI_LINK_CMDLINE, if the underlying
     if (NOT MPI_LINK_CMDLINE)
       SET(MPI_LINK_CMDLINE ${MPI_COMPILE_CMDLINE})
     endif (NOT MPI_LINK_CMDLINE)
-  else (MPICXX_RETURN EQUAL 0)
-    message(STATUS "Unable to determine MPI from MPI driver ${MPICXX}")
-  endif (MPICXX_RETURN EQUAL 0)
-endif (MPICXX)
+  else (MPI_COMPILER_RETURN EQUAL 0)
+    message(STATUS "Unable to determine MPI from MPI driver ${MPI_COMPILER}")
+  endif (MPI_COMPILER_RETURN EQUAL 0)
+endif (MPI_INCLUDE_PATH AND MPI_LIBRARY)
 
-if (NOT MPI_FORCE_RECONFIGURE)
-  # We don't actually have to reconfigure anything
+if (MPI_INCLUDE_PATH AND MPI_LIBRARY)
+  # Do nothing: we already have MPI_INCLUDE_PATH and MPI_LIBRARY in
+  # the cache, and we don't want to override those settings.
 elseif (MPI_COMPILE_CMDLINE)
   # Extract compile flags from the compile command line.
-  string(REGEX MATCHALL "-D([^\" ]+|\"[^\"]+\")" MPI_ALL_COMPILE_FLAGS ${MPI_COMPILE_CMDLINE})
+  string(REGEX MATCHALL "-D([^\" ]+|\"[^\"]+\")" MPI_ALL_COMPILE_FLAGS "${MPI_COMPILE_CMDLINE}")
   set(MPI_COMPILE_FLAGS_WORK)
   foreach(FLAG ${MPI_ALL_COMPILE_FLAGS})
     if (MPI_COMPILE_FLAGS_WORK)
@@ -100,17 +137,25 @@ elseif (MPI_COMPILE_CMDLINE)
   endforeach(FLAG)
 
   # Extract include paths from compile command line
-  string(REGEX MATCH "-I([^\" ]+|\"[^\"]+\")" MPI_INCLUDE_PATH ${MPI_COMPILE_CMDLINE})
-  string(REGEX REPLACE "^-I" "" MPI_INCLUDE_PATH ${MPI_INCLUDE_PATH})
-  string(REGEX REPLACE "//" "/" MPI_INCLUDE_PATH ${MPI_INCLUDE_PATH})
-
+  string(REGEX MATCHALL "-I([^\" ]+|\"[^\"]+\")" MPI_ALL_INCLUDE_PATHS "${MPI_COMPILE_CMDLINE}")
+  set(MPI_INCLUDE_PATH_WORK)
+  foreach(IPATH ${MPI_ALL_INCLUDE_PATHS})
+    string(REGEX REPLACE "^-I" "" IPATH ${IPATH})
+    string(REGEX REPLACE "//" "/" IPATH ${IPATH})
+    list(APPEND MPI_INCLUDE_PATH_WORK ${IPATH})
+  endforeach(IPATH)
+  
   # Extract linker paths from the link command line
-  string(REGEX MATCH "-L([^\" ]+|\"[^\"]+\")" MPI_LINK_PATH ${MPI_LINK_CMDLINE})
-  string(REGEX REPLACE "^-L" "" MPI_LINK_PATH ${MPI_LINK_PATH})
-  string(REGEX REPLACE "//" "/" MPI_LINK_PATH ${MPI_LINK_PATH})
+  string(REGEX MATCHALL "-L([^\" ]+|\"[^\"]+\")" MPI_ALL_LINK_PATHS "${MPI_LINK_CMDLINE}")
+  set(MPI_LINK_PATH)
+  foreach(LPATH ${MPI_ALL_LINK_PATHS})
+    string(REGEX REPLACE "^-L" "" LPATH ${LPATH})
+    string(REGEX REPLACE "//" "/" LPATH ${LPATH})
+    list(APPEND MPI_LINK_PATH ${LPATH})
+  endforeach(LPATH)
 
   # Extract linker flags from the link command line
-  string(REGEX MATCHALL "-Wl,([^\" ]+|\"[^\"]+\")" MPI_ALL_LINK_FLAGS ${MPI_LINK_CMDLINE})
+  string(REGEX MATCHALL "-Wl,([^\" ]+|\"[^\"]+\")" MPI_ALL_LINK_FLAGS "${MPI_LINK_CMDLINE}")
   set(MPI_LINK_FLAGS_WORK)
   foreach(FLAG ${MPI_ALL_LINK_FLAGS})
     if (MPI_LINK_FLAGS_WORK)
@@ -122,7 +167,7 @@ elseif (MPI_COMPILE_CMDLINE)
 
   # Extract the set of libraries to link against from the link command
   # line
-  string(REGEX MATCHALL "-l([^\" ]+|\"[^\"]+\")" MPI_LIBNAMES ${MPI_LINK_CMDLINE})
+  string(REGEX MATCHALL "-l([^\" ]+|\"[^\"]+\")" MPI_LIBNAMES "${MPI_LINK_CMDLINE}")
 
   # Determine full path names for all of the libraries that one needs
   # to link against in an MPI program
@@ -143,31 +188,23 @@ elseif (MPI_COMPILE_CMDLINE)
   # MPI_EXTRA_LIBRARY.
   list(LENGTH MPI_LIBRARIES MPI_NUMLIBS)
   if (MPI_NUMLIBS GREATER 0)
-    list(GET MPI_LIBRARIES 0 MPI_LIBRARY)
+    list(GET MPI_LIBRARIES 0 MPI_LIBRARY_WORK)
+    set(MPI_LIBRARY ${MPI_LIBRARY_WORK} CACHE FILEPATH "MPI library to link against" FORCE)
   else (MPI_NUMLIBS GREATER 0)
-    set(MPI_LIBRARY "MPI_LIBRARY-NOTFOUND")
+    set(MPI_LIBRARY "MPI_LIBRARY-NOTFOUND" CACHE STRING "MPI library to link against" FORCE)
   endif (MPI_NUMLIBS GREATER 0)
   if (MPI_NUMLIBS GREATER 1)
-    set(MPI_EXTRA_LIBRARY ${MPI_LIBRARIES})
-    list(REMOVE_AT MPI_EXTRA_LIBRARY 0)
+    set(MPI_EXTRA_LIBRARY_WORK ${MPI_LIBRARIES})
+    list(REMOVE_AT MPI_EXTRA_LIBRARY_WORK 0)
+    set(MPI_EXTRA_LIBRARY ${MPI_EXTRA_LIBRARY_WORK} CACHE STRING "Extra MPI libraries to link against" FORCE)
   else (MPI_NUMLIBS GREATER 1)
-    set(MPI_EXTRA_LIBRARY "MPI_EXTRA_LIBRARY-NOTFOUND")
+    set(MPI_EXTRA_LIBRARY "MPI_EXTRA_LIBRARY-NOTFOUND" CACHE STRING "Extra MPI libraries to link against" FORCE)
   endif (MPI_NUMLIBS GREATER 1)
 
   # Set up all of the appropriate cache entries
-  set(MPI_FOUND TRUE CACHE INTERNAL "Whether MPI was found" FORCE)
-
-  if (NOT MPI_FORCE_RECONFIGURE)
-    set(MPI_COMPILE_FLAGS ${MPI_COMPILE_FLAGS_WORK} CACHE STRING "MPI compilation flags")
-    set(MPI_INCLUDE_PATH ${MPI_INCLUDE_PATH} CACHE STRING "MPI include path")
-    set(MPI_LINK_FLAGS ${MPI_LINK_FLAGS_WORK} CACHE STRING "MPI linking flags")
-    set(MPI_LIBRARIES ${MPI_LIBRARIES} CACHE STRING "MPI libraries to link against, separated by semicolons")
-  else (NOT MPI_FORCE_RECONFIGURE)
-    set(MPI_COMPILE_FLAGS ${MPI_COMPILE_FLAGS_WORK} CACHE STRING "MPI compilation flags" FORCE)
-    set(MPI_INCLUDE_PATH ${MPI_INCLUDE_PATH} CACHE STRING "MPI include path" FORCE)
-    set(MPI_LINK_FLAGS ${MPI_LINK_FLAGS_WORK} CACHE STRING "MPI linking flags" FORCE)
-    set(MPI_LIBRARIES ${MPI_LIBRARIES} CACHE STRING "MPI libraries to link against, separated by semicolons" FORCE)
-  endif (NOT MPI_FORCE_RECONFIGURE)
+  set(MPI_COMPILE_FLAGS ${MPI_COMPILE_FLAGS_WORK} CACHE STRING "MPI compilation flags" FORCE)
+  set(MPI_INCLUDE_PATH ${MPI_INCLUDE_PATH_WORK} CACHE STRING "MPI include path" FORCE)
+  set(MPI_LINK_FLAGS ${MPI_LINK_FLAGS_WORK} CACHE STRING "MPI linking flags" FORCE)
 else (MPI_COMPILE_CMDLINE)
   find_path(MPI_INCLUDE_PATH mpi.h 
     /usr/local/include 
@@ -176,16 +213,16 @@ else (MPI_COMPILE_CMDLINE)
     /usr/local/mpi/include
     "C:/Program Files/MPICH/SDK/Include" 
     "$ENV{SystemDrive}/Program Files/MPICH2/include"
-    "C:/Program Files/Microsoft Compute Cluster Pack/Include"
+    "$ENV{SystemDrive}/Program Files/Microsoft Compute Cluster Pack/Include"
     )
   
-  # TODO: How do we know whether we're building 32-bit vs. 64-bit?
+  # TODO: How do we know whether we're building 32-bit vs. 64-bit for MS-MPI?
   find_library(MPI_LIBRARY 
     NAMES mpi mpich
     PATHS /usr/lib /usr/local/lib /usr/local/mpi/lib
     "C:/Program Files/MPICH/SDK/Lib" 
     "$ENV{SystemDrive}/Program Files/MPICH/SDK/Lib"
-    "C:/Program Files/Microsoft Compute Cluster Pack/Lib/i386"
+    "$ENV{SystemDrive}/Program Files/Microsoft Compute Cluster Pack/Lib/i386"
     )
   find_library(MPI_LIBRARY 
     NAMES mpich2
@@ -196,24 +233,11 @@ else (MPI_COMPILE_CMDLINE)
     NAMES mpi++
     PATHS /usr/lib /usr/local/lib /usr/local/mpi/lib
     "C:/Program Files/MPICH/SDK/Lib" 
-    "C:/Program Files/Microsoft Compute Cluster Pack/Lib/i386"
-    DOC "If a second MPI library is necessary, specify it here.")
+    DOC "Extra MPI libraries to link against.")
 
   set(MPI_COMPILE_FLAGS "" CACHE STRING "MPI compilation flags")
   set(MPI_LINK_FLAGS "" CACHE STRING "MPI linking flags")
-
-  if (MPI_EXTRA_LIBRARY)
-    set(MPI_LIBRARIES "${MPI_LIBRARY};${MPI_EXTRA_LIBRARY}" CACHE STRING "MPI libraries to link against, separated by semicolons")
-  else (MPI_EXTRA_LIBRARY)
-    set(MPI_LIBRARIES ${MPI_LIBRARY} CACHE STRING "MPI libraries to link against, separated by semicolons")
-  endif (MPI_EXTRA_LIBRARY)
-
-  if (MPI_LIBRARY)
-    set(MPI_FOUND TRUE CACHE INTERNAL "Whether MPI was found" FORCE)
-  else (MPI_LIBRARY)
-    set(MPI_FOUND FALSE CACHE INTERNAL "Whether MPI was found" FORCE)
-  endif (MPI_LIBRARY)
-endif (NOT MPI_FORCE_RECONFIGURE)
+endif (MPI_INCLUDE_PATH AND MPI_LIBRARY)
 
 # on BlueGene/L the MPI lib is named libmpich.rts.a, there also these additional libs are required
 if("${MPI_LIBRARY}" MATCHES "mpich.rts")
@@ -221,10 +245,22 @@ if("${MPI_LIBRARY}" MATCHES "mpich.rts")
    set(MPI_LIBRARY ${MPI_LIBRARY}  msglayer.rts devices.rts rts.rts devices.rts)
 endif("${MPI_LIBRARY}" MATCHES "mpich.rts")
 
-set(MPI_LIBRARY ${MPI_LIBRARY} CACHE INTERNAL "MPI library to link against. Deprecated: use MPI_LIBRARIES instead")
-set(MPI_EXTRA_LIBRARY ${MPI_EXTRA_LIBRARY} CACHE INTERNAL "Second MPI library to link against. Deprecated: use MPI_LIBRARIES instead")
+# Set up extra variables to conform to 
+if (MPI_EXTRA_LIBRARY)
+  set(MPI_LIBRARIES ${MPI_LIBRARY} ${MPI_EXTRA_LIBRARY})
+else (MPI_EXTRA_LIBRARY)
+  set(MPI_LIBRARIES ${MPI_LIBRARY})
+endif (MPI_EXTRA_LIBRARY)
+
+if (MPI_INCLUDE_PATH AND MPI_LIBRARY)
+  set(MPI_FOUND TRUE)
+else (MPI_INCLUDE_PATH AND MPI_LIBRARY)
+  set(MPI_FOUND FALSE)
+endif (MPI_INCLUDE_PATH AND MPI_LIBRARY)
 
 include(FindPackageHandleStandardArgs)
 # handle the QUIETLY and REQUIRED arguments 
 find_package_handle_standard_args(MPI DEFAULT_MSG MPI_LIBRARY MPI_INCLUDE_PATH)
-mark_as_advanced(MPI_INCLUDE_PATH MPI_COMPILE_FLAGS MPI_LINK_FLAGS MPI_LIBRARIES)
+
+mark_as_advanced(MPI_INCLUDE_PATH MPI_COMPILE_FLAGS MPI_LINK_FLAGS MPI_LIBRARY 
+  MPI_EXTRA_LIBRARY)
diff --git a/Source/cmComputeLinkDepends.cxx b/Source/cmComputeLinkDepends.cxx
index 5005e962cf..e232525a2b 100644
--- a/Source/cmComputeLinkDepends.cxx
+++ b/Source/cmComputeLinkDepends.cxx
@@ -169,6 +169,9 @@ cmComputeLinkDepends
 
   // Enable debug mode if requested.
   this->DebugMode = this->Makefile->IsOn("CMAKE_LINK_DEPENDS_DEBUG_MODE");
+
+  // Assume no compatibility until set.
+  this->OldLinkDirMode = false;
 }
 
 //----------------------------------------------------------------------------
@@ -183,6 +186,12 @@ cmComputeLinkDepends::~cmComputeLinkDepends()
 }
 
 //----------------------------------------------------------------------------
+void cmComputeLinkDepends::SetOldLinkDirMode(bool b)
+{
+  this->OldLinkDirMode = b;
+}
+
+//----------------------------------------------------------------------------
 std::vector<cmComputeLinkDepends::LinkEntry> const&
 cmComputeLinkDepends::Compute()
 {
@@ -460,6 +469,10 @@ void cmComputeLinkDepends::AddVarLinkEntries(int depender_index,
         {
         actual_libs.push_back(*di);
         }
+      else if(this->OldLinkDirMode)
+        {
+        this->CheckWrongConfigItem(*di);
+        }
 
       // Reset the link type until another explicit type is given.
       llt = cmTarget::GENERAL;
@@ -492,6 +505,10 @@ cmComputeLinkDepends::AddTargetLinkEntries(int depender_index,
       {
       actual_libs.push_back(li->first);
       }
+    else if(this->OldLinkDirMode)
+      {
+      this->CheckWrongConfigItem(li->first);
+      }
     }
 
   // Add these entries.
@@ -809,3 +826,23 @@ void cmComputeLinkDepends::DisplayFinalEntries()
     }
   fprintf(stderr, "\n");
 }
+
+//----------------------------------------------------------------------------
+void cmComputeLinkDepends::CheckWrongConfigItem(std::string const& item)
+{
+  if(!this->OldLinkDirMode)
+    {
+    return;
+    }
+
+  // For CMake 2.4 bug-compatibility we need to consider the output
+  // directories of targets linked in another configuration as link
+  // directories.
+  if(cmTarget* tgt = this->Makefile->FindTargetToUse(item.c_str()))
+    {
+    if(!tgt->IsImported())
+      {
+      this->OldWrongConfigItems.insert(tgt);
+      }
+    }
+}
diff --git a/Source/cmComputeLinkDepends.h b/Source/cmComputeLinkDepends.h
index de85fa0ff2..49e8d6b4b6 100644
--- a/Source/cmComputeLinkDepends.h
+++ b/Source/cmComputeLinkDepends.h
@@ -54,6 +54,10 @@ public:
   typedef std::vector<LinkEntry> EntryVector;
   EntryVector const& Compute();
 
+  void SetOldLinkDirMode(bool b);
+  std::set<cmTarget*> const& GetOldWrongConfigItems() const
+    { return this->OldWrongConfigItems; }
+
 private:
 
   // Context information.
@@ -128,6 +132,11 @@ private:
   void VisitComponent(cmComputeComponentGraph const& ccg, unsigned int i);
   void EmitComponent(NodeList const& nl);
   void DisplayFinalEntries();
+
+  // Compatibility help.
+  bool OldLinkDirMode;
+  void CheckWrongConfigItem(std::string const& item);
+  std::set<cmTarget*> OldWrongConfigItems;
 };
 
 #endif
diff --git a/Source/cmComputeLinkInformation.cxx b/Source/cmComputeLinkInformation.cxx
index 82db1d3e25..fc9bf47438 100644
--- a/Source/cmComputeLinkInformation.cxx
+++ b/Source/cmComputeLinkInformation.cxx
@@ -510,6 +510,7 @@ bool cmComputeLinkInformation::Compute()
 
   // Compute the ordered link line items.
   cmComputeLinkDepends cld(this->Target, this->Config);
+  cld.SetOldLinkDirMode(this->OldLinkDirMode);
   cmComputeLinkDepends::EntryVector const& linkEntries = cld.Compute();
 
   // Add the link line items.
@@ -539,6 +540,25 @@ bool cmComputeLinkInformation::Compute()
     this->SetCurrentLinkType(this->StartLinkType);
     }
 
+  // Finish listing compatibility paths.
+  if(this->OldLinkDirMode)
+    {
+    // For CMake 2.4 bug-compatibility we need to consider the output
+    // directories of targets linked in another configuration as link
+    // directories.
+    std::set<cmTarget*> const& wrongItems = cld.GetOldWrongConfigItems();
+    for(std::set<cmTarget*>::const_iterator i = wrongItems.begin();
+        i != wrongItems.end(); ++i)
+      {
+      cmTarget* tgt = *i;
+      bool implib =
+        (this->UseImportLibrary &&
+         (tgt->GetType() == cmTarget::SHARED_LIBRARY));
+      std::string lib = tgt->GetFullPath(this->Config , implib, true);
+      this->OldLinkDirItems.push_back(lib);
+      }
+    }
+
   // Finish setting up linker search directories.
   if(!this->FinishLinkerSearchDirectories())
     {
diff --git a/Source/cmExportFileGenerator.cxx b/Source/cmExportFileGenerator.cxx
index 914b044778..1e0a8d92cb 100644
--- a/Source/cmExportFileGenerator.cxx
+++ b/Source/cmExportFileGenerator.cxx
@@ -79,12 +79,14 @@ bool cmExportFileGenerator::GenerateImportFile()
     }
   std::ostream& os = *foutPtr;
 
-  // Start with the import file header.
+  // Isolate the file policy level.
+  // We use 2.6 here instead of the current version because newer
+  // versions of CMake should be able to export files imported by 2.6
+  // until the import format changes.
   os << "CMAKE_POLICY(PUSH)\n"
-     << "CMAKE_POLICY(VERSION "
-     << cmVersion::GetMajorVersion() << "."
-     << cmVersion::GetMinorVersion() << "."
-     << cmVersion::GetPatchVersion() << ")\n";
+     << "CMAKE_POLICY(VERSION 2.6)\n";
+
+  // Start with the import file header.
   this->GenerateImportHeaderCode(os);
 
   // Create all the imported targets.
diff --git a/Source/cmListFileCache.cxx b/Source/cmListFileCache.cxx
index 27a4878b94..c7383eafe4 100644
--- a/Source/cmListFileCache.cxx
+++ b/Source/cmListFileCache.cxx
@@ -171,30 +171,12 @@ bool cmListFile::ParseFile(const char* filename,
       
       if (isProblem)
       {
-      cmOStringStream msg;
-      msg << "No cmake_minimum_required command is present.  "
-          << "A line of code such as\n"
-          << "  cmake_minimum_required(VERSION "
-          << cmVersion::GetMajorVersion() << "."
-          << cmVersion::GetMinorVersion()
-          << ")\n"
-          << "should be added at the top of the file.  "
-          << "The version specified may be lower if you wish to "
-          << "support older CMake versions for this project.  "
-          << "For more information run "
-          << "\"cmake --help-policy CMP0000\".";
-      switch (mf->GetPolicyStatus(cmPolicies::CMP0000))
-        {
-        case cmPolicies::WARN:
-          mf->IssueMessage(cmake::AUTHOR_WARNING, msg.str().c_str());
-        case cmPolicies::OLD:
-          // Implicitly set the version for the user.
-          mf->SetPolicyVersion("2.4");
-          break;
-        default:
-          mf->IssueMessage(cmake::FATAL_ERROR, msg.str().c_str());
-          return false;
-        }
+      // Tell the top level cmMakefile to diagnose
+      // this violation of CMP0000.
+      mf->SetCheckCMP0000(true);
+
+      // Implicitly set the version for the user.
+      mf->SetPolicyVersion("2.4");
       }
     }
   }
diff --git a/Source/cmLocalVisualStudio7Generator.cxx b/Source/cmLocalVisualStudio7Generator.cxx
index 5d30c5945e..7ee40fc128 100644
--- a/Source/cmLocalVisualStudio7Generator.cxx
+++ b/Source/cmLocalVisualStudio7Generator.cxx
@@ -31,6 +31,8 @@
 
 #include <ctype.h> // for isspace
 
+static bool cmLVS6G_IsFAT(const char* dir);
+
 class cmLocalVisualStudio7GeneratorInternals
 {
 public:
@@ -661,16 +663,21 @@ void cmLocalVisualStudio7Generator::WriteConfiguration(std::ostream& fout,
   fout << "\t\t\t\tInterfaceIdentifierFileName=\"$(InputName)_i.c\"\n";
   fout << "\t\t\t\tProxyFileName=\"$(InputName)_p.c\"/>\n";
   // end of <Tool Name=VCMIDLTool
-  
-  // If we are building a version 8 project file, add a flag telling the
-  // manifest tool to use a workaround for FAT32 file systems, which can cause
-  // an empty manifest to be embedded into the resulting executable.
-  // See CMake bug #2617.
+
+  // Check if we need the FAT32 workaround.
   if ( this->Version >= 8 )
     {
-    fout << "\t\t\t<Tool\n\t\t\t\tName=\"VCManifestTool\"\n"
-         << "\t\t\t\tUseFAT32Workaround=\"true\"\n"
-         << "\t\t\t/>\n";
+    // Check the filesystem type where the target will be written.
+    if(cmLVS6G_IsFAT(target.GetDirectory(configName)))
+      {
+      // Add a flag telling the manifest tool to use a workaround
+      // for FAT32 file systems, which can cause an empty manifest
+      // to be embedded into the resulting executable.  See CMake
+      // bug #2617.
+      fout << "\t\t\t<Tool\n\t\t\t\tName=\"VCManifestTool\"\n"
+           << "\t\t\t\tUseFAT32Workaround=\"true\"\n"
+           << "\t\t\t/>\n";
+      }
     }
 
   this->OutputTargetRules(fout, configName, target, libName);
@@ -2054,3 +2061,21 @@ GetTargetObjectFileDirectories(cmTarget* target,
   dir += this->GetGlobalGenerator()->GetCMakeCFGInitDirectory();
   dirs.push_back(dir);
 }
+
+//----------------------------------------------------------------------------
+#include <windows.h>
+static bool cmLVS6G_IsFAT(const char* dir)
+{
+  if(dir[0] && dir[1] == ':')
+    {
+    char volRoot[4] = "_:/";
+    volRoot[0] = dir[0];
+    char fsName[16];
+    if(GetVolumeInformation(volRoot, 0, 0, 0, 0, 0, fsName, 16) &&
+       strstr(fsName, "FAT") != 0)
+      {
+      return true;
+      }
+    }
+  return false;
+}
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index f09c605e80..135dc287d9 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -146,6 +146,10 @@ void cmMakefile::Initialize()
 
   // Enter a policy level for this directory.
   this->PushPolicy();
+
+  // By default the check is not done.  It is enabled by
+  // cmListFileCache in the top level if necessary.
+  this->CheckCMP0000 = false;
 }
 
 unsigned int cmMakefile::GetCacheMajorVersion()
@@ -561,19 +565,11 @@ bool cmMakefile::ReadListFile(const char* filename_in,
       }
     }
 
-  // If this is the directory-level CMakeLists.txt file then enforce
-  // policy stack depth.
+  // If this is the directory-level CMakeLists.txt file then perform
+  // some extra checks.
   if(this->ListFileStack.size() == 1)
     {
-    while(this->PolicyStack.size() > 1)
-      {
-      if(endScopeNicely)
-        {
-        this->IssueMessage(cmake::FATAL_ERROR, 
-                           "cmake_policy PUSH without matching POP");
-        }
-      this->PopPolicy(false);
-      }
+    this->EnforceDirectoryLevelRules(endScopeNicely);
     }
 
   this->AddDefinition("CMAKE_PARENT_LIST_FILE", currentParentFile.c_str());
@@ -585,6 +581,55 @@ bool cmMakefile::ReadListFile(const char* filename_in,
   return true;
 }
 
+//----------------------------------------------------------------------------
+void cmMakefile::EnforceDirectoryLevelRules(bool endScopeNicely)
+{
+  // Enforce policy stack depth.
+  while(this->PolicyStack.size() > 1)
+    {
+    if(endScopeNicely)
+      {
+      this->IssueMessage(cmake::FATAL_ERROR,
+                         "cmake_policy PUSH without matching POP");
+      }
+    this->PopPolicy(false);
+    }
+
+  // Diagnose a violation of CMP0000 if necessary.
+  if(this->CheckCMP0000)
+    {
+    cmOStringStream msg;
+    msg << "No cmake_minimum_required command is present.  "
+        << "A line of code such as\n"
+        << "  cmake_minimum_required(VERSION "
+        << cmVersion::GetMajorVersion() << "."
+        << cmVersion::GetMinorVersion()
+        << ")\n"
+        << "should be added at the top of the file.  "
+        << "The version specified may be lower if you wish to "
+        << "support older CMake versions for this project.  "
+        << "For more information run "
+        << "\"cmake --help-policy CMP0000\".";
+    switch (this->GetPolicyStatus(cmPolicies::CMP0000))
+      {
+      case cmPolicies::WARN:
+        // Warn because the user did not provide a mimimum required
+        // version.
+        this->IssueMessage(cmake::AUTHOR_WARNING, msg.str().c_str());
+      case cmPolicies::OLD:
+        // OLD behavior is to use policy version 2.4 set in
+        // cmListFileCache.
+        break;
+      case cmPolicies::REQUIRED_IF_USED:
+      case cmPolicies::REQUIRED_ALWAYS:
+      case cmPolicies::NEW:
+        // NEW behavior is to issue an error.
+        this->IssueMessage(cmake::FATAL_ERROR, msg.str().c_str());
+        cmSystemTools::SetFatalErrorOccured();
+        return;
+      }
+    }
+}
 
 void cmMakefile::AddCommand(cmCommand* wg)
 {
diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index b91ddb45e7..d8873f4c6b 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -793,6 +793,9 @@ public:
   void IssueMessage(cmake::MessageType t,
                     std::string const& text) const;
 
+  /** Set whether or not to report a CMP0000 violation.  */
+  void SetCheckCMP0000(bool b) { this->CheckCMP0000 = b; }
+
 protected:
   // add link libraries and directories to the target
   void AddGlobalLinkInformation(const char* name, cmTarget& target);
@@ -904,6 +907,11 @@ private:
   typedef std::map<cmPolicies::PolicyID,
                    cmPolicies::PolicyStatus> PolicyMap;
   std::vector<PolicyMap> PolicyStack;
+
+  bool CheckCMP0000;
+
+  // Enforce rules about CMakeLists.txt files.
+  void EnforceDirectoryLevelRules(bool endScopeNicely);
 };
 
 
diff --git a/Source/cmPolicies.cxx b/Source/cmPolicies.cxx
index b37171b785..b69a7198e5 100644
--- a/Source/cmPolicies.cxx
+++ b/Source/cmPolicies.cxx
@@ -101,7 +101,15 @@ cmPolicies::cmPolicies()
     "(such as \"2.6\").  "
     "The command will ensure that at least the given version of CMake is "
     "running and help newer versions be compatible with the project.  "
-    "See documentation of cmake_minimum_required for details.",
+    "See documentation of cmake_minimum_required for details.\n"
+    "Note that the command invocation must appear in the CMakeLists.txt "
+    "file itself; a call in an included file is not sufficient.  "
+    "However, the cmake_policy command may be called to set policy "
+    "CMP0000 to OLD or NEW behavior explicitly.  "
+    "The OLD behavior is to silently ignore the missing invocation.  "
+    "The NEW behavior is to issue an error instead of a warning.  "
+    "An included file may set CMP0000 explicitly to affect how this "
+    "policy is enforced for the main CMakeLists.txt file.",
     2,6,0, cmPolicies::WARN
     );