ENH: fix qt version detection

Modules/FindQt4.cmake

@@ -212,9 +212,9 @@ IF (QT_QMAKE_EXECUTABLE)
       ENDIF (NOT req_qt_major_vers EQUAL 4)
 
       # and now the version string given by qmake
-      STRING(REGEX REPLACE "([0-9]+)\\.[0-9]+\\.[0-9]+" "\\1" found_qt_major_vers "${QTVERSION}")
-      STRING(REGEX REPLACE "[0-9]+\\.([0-9])+\\.[0-9]+" "\\1" found_qt_minor_vers "${QTVERSION}")
-      STRING(REGEX REPLACE "[0-9]+\\.[0-9]+\\.([0-9]+)" "\\1" found_qt_patch_vers "${QTVERSION}")
+      STRING(REGEX REPLACE "([0-9]+)\\.[0-9]+\\.[0-9]+" "\\1" found_qt_major_vers "${qt_version_tmp}")
+      STRING(REGEX REPLACE "[0-9]+\\.([0-9])+\\.[0-9]+" "\\1" found_qt_minor_vers "${qt_version_tmp}")
+      STRING(REGEX REPLACE "[0-9]+\\.[0-9]+\\.([0-9]+)" "\\1" found_qt_patch_vers "${qt_version_tmp}")
 
       # compute an overall version number which can be compared at once
       MATH(EXPR req_vers "${req_qt_major_vers}*10000 + ${req_qt_minor_vers}*100 + ${req_qt_patch_vers}")