COMP: Update FTD2XX external project to support reuse from application

Introduce variables FTD2XX_DLL_DIR, FTD2XX_DLL_NAME, FTD2XX_LIB_DIR
and FTD2XX_LIB_NAME for use in application implementing their own
external project including the ones provided by iMSTK.

It ensures the install subdirectory exists when custom location is
specified.

CMake/External/External_FTD2XX.cmake

@@ -6,17 +6,32 @@ endif()
 
 include(imstkAddExternalProject)
 
-# Set FTD2XX_SOURCE_DIR
+# Set FTD2XX_SOURCE_DIR and FTD2XX_PREFIX
 imstk_define_external_dirs( FTD2XX )
 
+# Directories and filenames specific to the FTD2XX archive layout
+set(_dll_dir "i386")
+set(_dll_name "ftd2xx.dll")
+set(_lib_dir "i386")
+set(_lib_name "ftd2xx.lib")
+if("${CMAKE_SIZEOF_VOID_P}" STREQUAL "8")
+  set(_dll_dir "amd64")
+  set(_dll_name "ftd2xx64.dll")
+  set(_lib_dir "amd64")
+  set(_lib_name "ftd2xx.lib")
+endif()
+
+# Directories and filenames specific to the FTD2XX install layout
+set(FTD2XX_DLL_DIR "bin")
+set(FTD2XX_DLL_NAME "${_dll_name}")
+set(FTD2XX_LIB_DIR "lib")
+set(FTD2XX_LIB_NAME "${_lib_name}")
+
 #-----------------------------------------------------------------------------
 # Set install commands
 #-----------------------------------------------------------------------------
-set(FTD2XX_INSTALL_DIR ${CMAKE_INSTALL_PREFIX})
-
-set(ftd2xx_libdir "i386")
-if("${CMAKE_SIZEOF_VOID_P}" STREQUAL "8")
-  set(ftd2xx_libdir "amd64")
+if(CMAKE_PROJECT_NAME STREQUAL "iMSTK")
+  set(FTD2XX_INSTALL_DIR ${CMAKE_INSTALL_PREFIX})
 endif()
 
 set(copy_ftd2xx_headers_command
@@ -26,25 +41,36 @@ set(copy_ftd2xx_headers_command
   )
 set(copy_ftd2xx_lib_command
   ${CMAKE_COMMAND} -E copy
-  ${FTD2XX_SOURCE_DIR}/${ftd2xx_libdir}/ftd2xx.lib
-  ${FTD2XX_INSTALL_DIR}/lib/ftd2xx.lib
+  ${FTD2XX_SOURCE_DIR}/${_lib_dir}/${_lib_name}
+  ${FTD2XX_INSTALL_DIR}/${FTD2XX_LIB_DIR}/${_lib_name}
   )
-  
 set(copy_ftd2xx_dll_command
   ${CMAKE_COMMAND} -E copy
-  ${FTD2XX_SOURCE_DIR}/${ftd2xx_libdir}/ftd2xx64.dll
-  ${FTD2XX_INSTALL_DIR}/bin/ftd2xx64.dll
+  ${FTD2XX_SOURCE_DIR}/${_dll_dir}/${_dll_name}
+  ${FTD2XX_INSTALL_DIR}/${FTD2XX_DLL_DIR}/${_dll_name}
   )
 
-# HS 2021-aug-08 Some dependencies expect the dll name to 
-# be ftd2xx.dll rather than ftd2xx64.dll we're copying here
-# to the renamed version as the whole chain is built via 64 bit builds
-set(copy_ftd2xx_dll_command_rename
-  ${CMAKE_COMMAND} -E copy
-  ${FTD2XX_SOURCE_DIR}/${ftd2xx_libdir}/ftd2xx64.dll
-  ${FTD2XX_INSTALL_DIR}/bin/ftd2xx.dll
+set(FTD2XX_INSTALL_COMMAND
+  INSTALL_COMMAND
+    COMMAND ${copy_ftd2xx_headers_command}
+    COMMAND ${copy_ftd2xx_lib_command}
+    COMMAND ${copy_ftd2xx_dll_command}
   )
 
+if("${CMAKE_SIZEOF_VOID_P}" STREQUAL "8")
+  # HS 2021-aug-08 Some dependencies expect the dll name to
+  # be ftd2xx.dll rather than ftd2xx64.dll we're copying here
+  # to the renamed version as the whole chain is built via 64 bit builds
+  set(copy_ftd2xx_dll_command_rename
+    ${CMAKE_COMMAND} -E copy
+    ${FTD2XX_SOURCE_DIR}/${_lib_dir}/ftd2xx64.dll
+    ${FTD2XX_INSTALL_DIR}/bin/ftd2xx.dll
+    )
+
+  list(APPEND FTD2XX_INSTALL_COMMAND
+    COMMAND ${copy_ftd2xx_dll_command_rename}
+    )
+endif()
 
 #-----------------------------------------------------------------------------
 # Add External Project
@@ -57,11 +83,7 @@ imstk_add_external_project( FTD2XX
   UPDATE_COMMAND ${SKIP_STEP_COMMAND}
   CONFIGURE_COMMAND ${SKIP_STEP_COMMAND}
   BUILD_COMMAND ${SKIP_STEP_COMMAND}
-  INSTALL_COMMAND
-    COMMAND ${copy_ftd2xx_headers_command}
-    COMMAND ${copy_ftd2xx_lib_command}
-    COMMAND ${copy_ftd2xx_dll_command}
-    COMMAND ${copy_ftd2xx_dll_command_rename}
+  ${FTD2XX_INSTALL_COMMAND}
   RELATIVE_INCLUDE_PATH "/"
   #VERBOSE
 )