ENH: Add option to allow to always trigger otb build step from superbuild tree

SuperBuild/CMake/External_otb.cmake

@@ -26,7 +26,12 @@ set(OTB_SB_SRC ${CMAKE_SOURCE_DIR}/..)
 
 ADDTO_DEPENDENCIES_IF_NOT_SYSTEM(OTB GDAL OSSIM ITK TINYXML BOOST)
 
-##get_property(OTB_DEPENDENCIES GLOBAL PROPERTY GLOBAL_OTB_DEPENDENCIES)
+# Check BUILD_ALWAYS option
+if(BUILD_ALWAYS)
+  set(OTB_BUILD_ALWAYS_OPTION 1)
+else()
+  set(OTB_BUILD_ALWAYS_OPTION 0)
+endif()
 
 if(OTB_USE_CURL)
   ADDTO_DEPENDENCIES_IF_NOT_SYSTEM(OTB CURL)
@@ -181,6 +186,7 @@ ExternalProject_Add(OTB
   BINARY_DIR ${OTB_SB_BUILD_DIR}
   INSTALL_DIR ${CMAKE_INSTALL_PREFIX}
   DOWNLOAD_DIR ${DOWNLOAD_LOCATION}
+  BUILD_ALWAYS ${OTB_BUILD_ALWAYS_OPTION}
   CMAKE_CACHE_ARGS
   ${SB_CMAKE_CACHE_ARGS}
   ${OTB_MODULES_CONFIG}
@@ -224,7 +230,7 @@ ExternalProject_Add_Step(
 
   COMMAND ${CMAKE_COMMAND} -E copy
   ${OTB_SB_SRC}/NOTICE ${CMAKE_INSTALL_PREFIX}/share/copyright/NOTICE
-  
+
   COMMAND ${CMAKE_COMMAND}
   -E copy_directory
   ${CMAKE_SOURCE_DIR}/Copyright ${CMAKE_INSTALL_PREFIX}/share/copyright

SuperBuild/CMakeLists.txt

@@ -52,6 +52,7 @@ endif()
 
 option(BUILD_SHARED_LIBS "Build OTB with shared libraries." ON)
 option(BUILD_STATIC_LIBS "Build with static libraries." OFF)
+option(BUILD_ALWAYS "Always build or install OTB." OFF)
 option(WITH_REMOTE_MODULES "Build with specific list of remote modules." OFF)
 option(OTB_USE_OPENMP "use openmp" OFF)
 set(OTB_ADDITIONAL_CACHE "" CACHE STRING "Additional cmake option for OTB -DVAR:TYPE=VALUE ...")
@@ -317,7 +318,7 @@ option(OTB_USE_OPENGL "Enable module OpenGL in OTB" ON)
 option(OTB_USE_GLEW "Enable module GLEW in OTB" ON)
 
 #Cannot activate GLUT on OSX. See Mantis issue #1194")
-# do not activate GLFW by default on osx. see failing test 
+# do not activate GLFW by default on osx. see failing test
 # https://dash.orfeo-toolbox.org/testDetails.php?test=59844554&build=287120
 if(APPLE)
   option(OTB_USE_GLUT "Enable module GLUT in OTB" OFF)