FindPythonLibs: honor EXACT version specification (#13216)

Modules/FindPythonLibs.cmake

@@ -45,13 +45,19 @@ IF(PythonLibs_FIND_VERSION)
         STRING(REGEX REPLACE "^([0-9]+\\.[0-9]+).*" "\\1" _PYTHON_FIND_MAJ_MIN "${PythonLibs_FIND_VERSION}")
         STRING(REGEX REPLACE "^([0-9]+).*" "\\1" _PYTHON_FIND_MAJ "${_PYTHON_FIND_MAJ_MIN}")
         UNSET(_PYTHON_FIND_OTHER_VERSIONS)
-        IF(NOT PythonLibs_FIND_VERSION_EXACT)
+        IF(PythonLibs_FIND_VERSION_EXACT)
+            IF(_PYTHON_FIND_MAJ_MIN STREQUAL PythonLibs_FIND_VERSION)
+                SET(_PYTHON_FIND_OTHER_VERSIONS "${PythonLibs_FIND_VERSION}")
+            ELSE(_PYTHON_FIND_MAJ_MIN STREQUAL PythonLibs_FIND_VERSION)
+                SET(_PYTHON_FIND_OTHER_VERSIONS "${PythonLibs_FIND_VERSION}" "${_PYTHON_FIND_MAJ_MIN}")
+            ENDIF(_PYTHON_FIND_MAJ_MIN STREQUAL PythonLibs_FIND_VERSION)
+        ELSE(PythonLibs_FIND_VERSION_EXACT)
             FOREACH(_PYTHON_V ${_PYTHON${_PYTHON_FIND_MAJ}_VERSIONS})
                 IF(NOT _PYTHON_V VERSION_LESS _PYTHON_FIND_MAJ_MIN)
                     LIST(APPEND _PYTHON_FIND_OTHER_VERSIONS ${_PYTHON_V})
                 ENDIF()
              ENDFOREACH()
-        ENDIF(NOT PythonLibs_FIND_VERSION_EXACT)
+        ENDIF(PythonLibs_FIND_VERSION_EXACT)
         UNSET(_PYTHON_FIND_MAJ_MIN)
         UNSET(_PYTHON_FIND_MAJ)
     ELSE(PythonLibs_FIND_VERSION MATCHES "^[0-9]+\\.[0-9]+(\\.[0-9]+.*)?$")