SuperBuild: custom target(OTB_DEPENDS) to only build otb dependencies

SuperBuild/CMake/External_otb.cmake

@@ -105,10 +105,13 @@ if(MSVC)
   ADD_SUPERBUILD_CMAKE_VAR(OTB JPEG_LIBRARY)
 endif()
 
+if(MSVC)
+  set(_CXX_FLAGS )
+endif()
 
 # forward compilation flags
-set(OTB_SB_C_FLAGS "${SB_PRIOR_INCLUDE_FLAGS} ${CMAKE_C_FLAGS}")
-set(OTB_SB_CXX_FLAGS "${SB_PRIOR_INCLUDE_FLAGS} ${CMAKE_CXX_FLAGS}")
+set(OTB_SB_C_FLAGS "${SB_PRIOR_INCLUDE_FLAGS} ${CMAKE_C_FLAGS} ")
+set(OTB_SB_CXX_FLAGS "${SB_PRIOR_INCLUDE_FLAGS} ${CMAKE_CXX_FLAGS} /EHsc /DNOMINMAX")
 
 set(OTB_SB_COMPILATION_FLAGS
   -DCMAKE_C_FLAGS:STRING=${OTB_SB_C_FLAGS}
@@ -119,6 +122,13 @@ set(OTB_SB_COMPILATION_FLAGS
   -DCMAKE_STATIC_LINKER_FLAGS:STRING=${CMAKE_STATIC_LINKER_FLAGS}
   )
 
+add_custom_target(OTB_DEPENDS
+DEPENDS ${OTB_DEPENDENCIES}
+COMMAND -E echo "Building only otb dependencies: ${OTB_DEPENDENCIES}"
+WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
+COMMENT "Built all otb dependencies: ${OTB_DEPENDENCIES}"
+)
+
 ExternalProject_Add(OTB
   DEPENDS ${OTB_DEPENDENCIES}
   PREFIX OTB