diff --git a/Help/command/add_library.rst b/Help/command/add_library.rst
index f19b5c042..f86f3c5ec 100644
--- a/Help/command/add_library.rst
+++ b/Help/command/add_library.rst
@@ -94,7 +94,8 @@ object library name.  For example:
 
 will include objlib's object files in a library and an executable
 along with those compiled from their own sources.  Object libraries
-may contain only sources (and headers) that compile to object files.
+may contain only sources that compile, header files, and other files
+that would not affect linking of a normal library (e.g. ``.txt``).
 They may contain custom commands generating such sources, but not
 ``PRE_BUILD``, ``PRE_LINK``, or ``POST_BUILD`` commands.  Object libraries
 cannot be imported, exported, installed, or linked.  Some native build
diff --git a/Help/release/dev/allow-OBJECT-library-extra-sources.rst b/Help/release/dev/allow-OBJECT-library-extra-sources.rst
new file mode 100644
index 000000000..472fcdc50
--- /dev/null
+++ b/Help/release/dev/allow-OBJECT-library-extra-sources.rst
@@ -0,0 +1,6 @@
+allow-OBJECT-library-extra-sources
+----------------------------------
+
+* :ref:`Object Libraries` may now have extra sources that do not
+  compile to object files so long as they would not affect linking
+  of a normal library (e.g. ``.dat`` is okay but not ``.def``).
diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index eccb06ada..64c5822f8 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -38,7 +38,8 @@ void reportBadObjLib(std::vector<cmSourceFile*> const& badObjLib,
       {
       e << "  " << (*i)->GetLocation().GetName() << "\n";
       }
-    e << "but may contain only headers and sources that compile.";
+    e << "but may contain only sources that compile, header files, and "
+         "other files that would not affect linking of a normal library.";
     cm->IssueMessage(cmake::FATAL_ERROR, e.str(),
                      target->GetBacktrace());
     }
@@ -205,10 +206,6 @@ struct TagVisitor
     else
       {
       DoAccept<IsSameTag<Tag, ExtraSourcesTag>::Result>::Do(this->Data, sf);
-      if(this->IsObjLib && ext != "txt")
-        {
-        this->BadObjLibFiles.push_back(sf);
-        }
       }
   }
 };
diff --git a/Tests/ObjectLibrary/A/CMakeLists.txt b/Tests/ObjectLibrary/A/CMakeLists.txt
index 3fba9f816..c24c5ed92 100644
--- a/Tests/ObjectLibrary/A/CMakeLists.txt
+++ b/Tests/ObjectLibrary/A/CMakeLists.txt
@@ -11,5 +11,16 @@ add_custom_command(
                                    ${CMAKE_CURRENT_BINARY_DIR}/a1.c
   )
 
-add_library(A OBJECT a1.c a2.c)
+# Remove the custom command output to be sure it runs in an
+# incremental test.  Skip this on VS 6 because it sometimes
+# re-runs CMake after the custom command runs.
+if(NOT CMAKE_GENERATOR STREQUAL "Visual Studio 6")
+  file(REMOVE ${CMAKE_CURRENT_BINARY_DIR}/a.cmake)
+endif()
+add_custom_command(
+  OUTPUT a.cmake
+  COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_CURRENT_BINARY_DIR}/a.cmake
+  )
+
+add_library(A OBJECT a1.c a2.c a.cmake)
 target_include_directories(A PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
diff --git a/Tests/ObjectLibrary/CMakeLists.txt b/Tests/ObjectLibrary/CMakeLists.txt
index 75c34d825..e9f553e2b 100644
--- a/Tests/ObjectLibrary/CMakeLists.txt
+++ b/Tests/ObjectLibrary/CMakeLists.txt
@@ -12,6 +12,7 @@ add_library(Cshared SHARED c.c $<TARGET_OBJECTS:A> $<TARGET_OBJECTS:Bexport>)
 add_executable(UseCshared main.c)
 set_property(TARGET UseCshared PROPERTY COMPILE_DEFINITIONS SHARED_C)
 target_link_libraries(UseCshared Cshared)
+add_custom_command(TARGET UseCshared POST_BUILD COMMAND ${CMAKE_COMMAND} -P ${CMAKE_CURRENT_BINARY_DIR}/A/a.cmake)
 
 add_executable(UseCinternal main.c c.c $<TARGET_OBJECTS:A> $<TARGET_OBJECTS:B>)
 
diff --git a/Tests/RunCMake/ObjectLibrary/BadObjSource1-stderr.txt b/Tests/RunCMake/ObjectLibrary/BadObjSource1-stderr.txt
index b31225b48..a09552b76 100644
--- a/Tests/RunCMake/ObjectLibrary/BadObjSource1-stderr.txt
+++ b/Tests/RunCMake/ObjectLibrary/BadObjSource1-stderr.txt
@@ -3,6 +3,7 @@ CMake Error at BadObjSource1.cmake:1 \(add_library\):
 
     bad.def
 
-  but may contain only headers and sources that compile.
+  but may contain only sources that compile, header files, and other files
+  that would not affect linking of a normal library.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/ObjectLibrary/BadObjSource2-stderr.txt b/Tests/RunCMake/ObjectLibrary/BadObjSource2-stderr.txt
index 906cf0b64..b91ffd068 100644
--- a/Tests/RunCMake/ObjectLibrary/BadObjSource2-stderr.txt
+++ b/Tests/RunCMake/ObjectLibrary/BadObjSource2-stderr.txt
@@ -3,6 +3,7 @@ CMake Error at BadObjSource2.cmake:1 \(add_library\):
 
     bad.obj
 
-  but may contain only headers and sources that compile.
+  but may contain only sources that compile, header files, and other files
+  that would not affect linking of a normal library.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)