FindTclsh: support version selection

Modules/FindTCL.cmake

@@ -48,10 +48,14 @@ INCLUDE(CMakeFindFrameworks)
 INCLUDE(FindTclsh)
 INCLUDE(FindWish)
 
-GET_FILENAME_COMPONENT(TCL_TCLSH_PATH "${TCL_TCLSH}" PATH)
-GET_FILENAME_COMPONENT(TCL_TCLSH_PATH_PARENT "${TCL_TCLSH_PATH}" PATH)
-STRING(REGEX REPLACE 
-  "^.*tclsh([0-9]\\.*[0-9]).*$" "\\1" TCL_TCLSH_VERSION "${TCL_TCLSH}")
+IF(TCLSH_VERSION_STRING)
+  SET(TCL_TCLSH_VERSION "${TCLSH_VERSION_STRING}")
+ELSE(TCLSH_VERSION_STRING)
+  GET_FILENAME_COMPONENT(TCL_TCLSH_PATH "${TCL_TCLSH}" PATH)
+  GET_FILENAME_COMPONENT(TCL_TCLSH_PATH_PARENT "${TCL_TCLSH_PATH}" PATH)
+  STRING(REGEX REPLACE
+    "^.*tclsh([0-9]\\.*[0-9]).*$" "\\1" TCL_TCLSH_VERSION "${TCL_TCLSH}")
+ENDIF(TCLSH_VERSION_STRING)
 
 GET_FILENAME_COMPONENT(TK_WISH_PATH "${TK_WISH}" PATH)
 GET_FILENAME_COMPONENT(TK_WISH_PATH_PARENT "${TK_WISH_PATH}" PATH)

Modules/FindTclsh.cmake

@@ -82,9 +82,19 @@ FIND_PROGRAM(TCL_TCLSH
   HINTS ${TCLTK_POSSIBLE_BIN_PATHS}
   )
 
+IF(TCL_TCLSH)
+   EXECUTE_PROCESS(COMMAND "${CMAKE_COMMAND}" -E echo puts "\$tcl_version"
+                   COMMAND "${TCL_TCLSH}"
+                   OUTPUT_VARIABLE TCLSH_VERSION_STRING
+                   ERROR_QUIET
+                   OUTPUT_STRIP_TRAILING_WHITESPACE)
+ENDIF(TCL_TCLSH)
+
 # handle the QUIETLY and REQUIRED arguments and set TIFF_FOUND to TRUE if 
 # all listed variables are TRUE
 INCLUDE(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)
-FIND_PACKAGE_HANDLE_STANDARD_ARGS(Tclsh DEFAULT_MSG TCL_TCLSH)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(Tclsh
+                                  REQUIRED_VARS TCL_TCLSH
+                                  VERSION_VAR TCLSH_VERSION_STRING)
 
 MARK_AS_ADVANCED(TCL_TCLSH)