ENH: Added superbuild option CTK_USE_GIT_PROTOCOL

Since firewall doesn't always allow git protocol, turning off this option
will teach superbuild to use http protocol instead of git to clone repository.

Note also that git clone though http is slower

CMakeExternals/CTKData.cmake

@@ -14,7 +14,7 @@ IF(BUILD_TESTING)
   #   MESSAGE(STATUS "Adding project:${proj}")
     SET(CTKData_DEPENDS ${proj})
     ExternalProject_Add(${proj}
-        GIT_REPOSITORY git://github.com/commontk/CTKData.git
+        GIT_REPOSITORY ${git_protocol}://github.com/commontk/CTKData.git
         CONFIGURE_COMMAND ""
         BUILD_COMMAND ""
         INSTALL_COMMAND ""

CMakeExternals/DCMTK.cmake

@@ -17,7 +17,7 @@ IF(${add_project})
     SET(DCMTK_DEPENDS ${proj})
 
     ExternalProject_Add(${proj}
-        GIT_REPOSITORY "git://github.com/commontk/DCMTK.git"
+        GIT_REPOSITORY "${git_protocol}://github.com/commontk/DCMTK.git"
         CMAKE_GENERATOR ${gen}
         BUILD_COMMAND ""
         CMAKE_ARGS

CMakeExternals/Log4Qt.cmake

@@ -15,7 +15,7 @@ IF(${add_project})
 #     MESSAGE(STATUS "Adding project:${proj}")
     SET(Log4Qt_DEPENDS ${proj})
     ExternalProject_Add(${proj}
-        GIT_REPOSITORY "git://github.com/commontk/Log4Qt.git"
+        GIT_REPOSITORY "${git_protocol}://github.com/commontk/Log4Qt.git"
         GIT_TAG "patched"
         CMAKE_GENERATOR ${gen}
         BUILD_COMMAND ""

CMakeExternals/PythonQt.cmake

@@ -22,7 +22,7 @@ IF(${add_project})
     ENDIF()
       
     ExternalProject_Add(${proj}
-      GIT_REPOSITORY "git://github.com/commontk/PythonQt.git"
+      GIT_REPOSITORY "${git_protocol}://github.com/commontk/PythonQt.git"
       GIT_TAG "patched"
       CMAKE_GENERATOR ${gen}
       BUILD_COMMAND ""

CMakeExternals/VTK.cmake

@@ -15,7 +15,7 @@ IF(${add_project})
 #     MESSAGE(STATUS "Adding project:${proj}")
     SET(VTK_DEPENDS ${proj})
     ExternalProject_Add(${proj}
-      GIT_REPOSITORY git://vtk.org/VTK.git
+      GIT_REPOSITORY ${git_protocol}://vtk.org/VTK.git
       INSTALL_COMMAND ""
       CMAKE_GENERATOR ${gen}
       CMAKE_ARGS

CMakeExternals/ZMQ.cmake

@@ -15,7 +15,7 @@ IF(${add_project})
   #   MESSAGE(STATUS "Adding project:${proj}")
     SET(ZMQ_DEPENDS ${proj})
     ExternalProject_Add(${proj}
-        GIT_REPOSITORY git://github.com/PatrickCheng/zeromq2.git
+        GIT_REPOSITORY ${git_protocol}://github.com/PatrickCheng/zeromq2.git
         INSTALL_COMMAND ""
         CMAKE_GENERATOR ${gen}
         CMAKE_ARGS

SuperBuild.cmake

@@ -44,6 +44,16 @@ IF(NOT EXISTS ${CTK_BINARY_DIR}/CTK-build/bin)
 ENDIF()
 
 #-----------------------------------------------------------------------------
+# Git protocole option
+#
+option(CTK_USE_GIT_PROTOCOL "If behind a firewall turn this OFF to use http instead." ON)
+
+set(git_protocol "git")
+if(NOT CTK_USE_GIT_PROTOCOL)
+  set(git_protocol "http")
+endif()
+
+#-----------------------------------------------------------------------------
 # Enable and setup External project global properties
 #
 INCLUDE(ExternalProject)