cmake-gui: Reference LGPLv2.1 when redistributing Qt

Download http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt and place
it as Licenses/LGPLv2.1.txt in our source tree.  When building cmake-gui,
use option CMake_GUI_DISTRIBUTE_WITH_Qt_LGPL to enable notification
in the "About" dialog of how the distribution of Qt is licensed.
Install the license file as ${CMAKE_ROOT}/Licenses/LGPLv2.1.txt so that
the dialog can display a path to it.

Licenses/README.rst

+Licenses
+========
+
+The CMake source tree is distributed under terms of the BSD 3-Clause license.
+
+This directory contains other license files that need to be packaged with
+binary distributions when certain third-party libraries are included.

Source/QtDialog/CMakeLists.txt

@@ -102,6 +102,13 @@ if(APPLE)
     MACOSX_PACKAGE_LOCATION Resources)
 endif()
 
+if(CMake_GUI_DISTRIBUTE_WITH_Qt_LGPL)
+  install(FILES ${CMake_SOURCE_DIR}/Licenses/LGPLv2.1.txt
+    DESTINATION ${CMAKE_DATA_DIR}/Licenses)
+  set_property(SOURCE CMakeSetupDialog.cxx
+    PROPERTY COMPILE_DEFINITIONS CMake_GUI_DISTRIBUTE_WITH_Qt_LGPL)
+endif()
+
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
 add_executable(cmake-gui WIN32 MACOSX_BUNDLE ${SRCS})

Source/QtDialog/CMakeSetupDialog.cxx

@@ -34,6 +34,7 @@
 #include "QCMakeCacheView.h"
 #include "AddCacheEntry.h"
 #include "FirstConfigure.h"
+#include "cmSystemTools.h"
 #include "cmVersion.h"
 
 QCMakeThread::QCMakeThread(QObject* p)
@@ -814,9 +815,19 @@ void CMakeSetupDialog::doAbout()
     "\n"
     "CMake GUI maintained by csimsoft,\n"
     "built using Qt %2 (qt-project.org).\n"
+#ifdef CMake_GUI_DISTRIBUTE_WITH_Qt_LGPL
+    "\n"
+    "The Qt Toolkit is Copyright (C) Digia Plc and/or its subsidiary(-ies).\n"
+    "Qt is licensed under terms of the GNU LGPLv2.1, available at:\n"
+    " \"%3\""
+#endif
     );
   msg = msg.arg(cmVersion::GetCMakeVersion());
   msg = msg.arg(qVersion());
+#ifdef CMake_GUI_DISTRIBUTE_WITH_Qt_LGPL
+  std::string lgpl = cmSystemTools::GetCMakeRoot()+"/Licenses/LGPLv2.1.txt";
+  msg = msg.arg(lgpl.c_str());
+#endif
 
   QDialog dialog;
   dialog.setWindowTitle(tr("About"));

Utilities/Release/dash2win64_release.cmake

@@ -13,6 +13,7 @@ CMAKE_SKIP_BOOTSTRAP_TEST:STRING=TRUE
 CMAKE_Fortran_COMPILER:FILEPATH=FALSE
 CMAKE_GENERATOR:INTERNAL=Unix Makefiles
 BUILD_QtDialog:BOOL:=TRUE
+CMake_GUI_DISTRIBUTE_WITH_Qt_LGPL:BOOL=TRUE
 QT_QMAKE_EXECUTABLE:FILEPATH=c:/Dashboards/Support/qt-build/Qt/bin/qmake.exe
 ")
 get_filename_component(path "${CMAKE_CURRENT_LIST_FILE}" PATH)

Utilities/Release/dashmacmini2_release.cmake

@@ -16,6 +16,7 @@ OPENSSL_SSL_LIBRARY:FILEPATH=/Users/kitware/openssl-1.0.1c-install/lib/libssl.a
 CMAKE_SKIP_BOOTSTRAP_TEST:STRING=TRUE
 CPACK_SYSTEM_NAME:STRING=Darwin-universal
 BUILD_QtDialog:BOOL=TRUE
+CMake_GUI_DISTRIBUTE_WITH_Qt_LGPL:BOOL=TRUE
 QT_QMAKE_EXECUTABLE:FILEPATH=/Users/kitware/Support/qt-4.8.0/install/bin/qmake
 ")
 get_filename_component(path "${CMAKE_CURRENT_LIST_FILE}" PATH)

Utilities/Release/dashmacmini5_release.cmake

@@ -18,6 +18,7 @@ CMAKE_OSX_DEPLOYMENT_TARGET:STRING=10.5
 CMAKE_SKIP_BOOTSTRAP_TEST:STRING=TRUE
 CPACK_SYSTEM_NAME:STRING=Darwin64-universal
 BUILD_QtDialog:BOOL=TRUE
+CMake_GUI_DISTRIBUTE_WITH_Qt_LGPL:BOOL=TRUE
 QT_QMAKE_EXECUTABLE:FILEPATH=/Users/kitware/Support/qt-4.8.0/install/bin/qmake
 ")
 get_filename_component(path "${CMAKE_CURRENT_LIST_FILE}" PATH)

Utilities/Release/magrathea_release.cmake

@@ -16,6 +16,7 @@ OPENSSL_INCLUDE_DIR:PATH=/home/kitware/openssl-1.0.1c-install/include
 OPENSSL_SSL_LIBRARY:FILEPATH=/home/kitware/openssl-1.0.1c-install/lib/libssl.a
 CPACK_SYSTEM_NAME:STRING=Linux-i386
 BUILD_QtDialog:BOOL:=TRUE
+CMake_GUI_DISTRIBUTE_WITH_Qt_LGPL:BOOL=TRUE
 QT_QMAKE_EXECUTABLE:FILEPATH=/home/kitware/qt-4.43-install/bin/qmake
 ")
 get_filename_component(path "${CMAKE_CURRENT_LIST_FILE}" PATH)