Disable tests if nihtest is too old.

CMakeLists.txt

@@ -51,10 +51,19 @@ ENDIF(NOT TARGET dist)
 ADD_DEFINITIONS("-DHAVE_CONFIG_H")
 
 find_program(NIHTEST nihtest)
+set(NIHTEST_REQUIRED_VERSION "1.4")
+
 if(RUN_REGRESS)
-  if (NOT NIHTEST)
+  if(NOT NIHTEST)
     message(WARNING "-- nihtest not found, regression testing disabled")
     set(RUN_REGRESS OFF)
+  else()
+    execute_process(COMMAND ${NIHTEST} --version OUTPUT_STRIP_TRAILING_WHITESPACE OUTPUT_VARIABLE NIHTEST_VERSION_RAW)
+    string(REGEX REPLACE "[^ ]* " "" NIHTEST_VERSION ${NIHTEST_VERSION_RAW})
+    if (${NIHTEST_VERSION} VERSION_LESS ${NIHTEST_REQUIRED_VERSION})
+      message(WARNING "-- nihtest ${NIHTEST_VERSION} too old, at least ${NIHTEST_REQUIRED_VERSION} required, regression testing disabled")
+      set(RUN_REGRESS OFF)
+    endif()
   endif()
 endif()