diff --git a/src/configure b/src/configure
index afeb37551d..724226ebcd 100755
--- a/src/configure
+++ b/src/configure
@@ -1511,13 +1511,13 @@ done
 test -n "$TR" || TR="NOT_FOUND"
 
 
-TRSTRINGS=`echo ABCdef | $TR '[a-z]' '[A-Z]' 2>/dev/null | grep ABCDEF`
-TRCLASS=`echo ABCdef | $TR '[:lower:]' '[:upper:]' 2>/dev/null | grep ABCDEF`
+TRSTRINGS="`echo ABCdef | $TR '[a-z]' '[A-Z]' 2>/dev/null | grep ABCDEF`"
+TRCLASS="`echo ABCdef | $TR '[:lower:]' '[:upper:]' 2>/dev/null | grep ABCDEF`"
 
 if test "$TRSTRINGS" = "ABCDEF"; then
   TRARGS="'[a-z]' '[A-Z]'"
 elif test "$TRCLASS" = "ABCDEF"; then
-  TRARGS="\"[:lower:]\" \"[:upper:]\""
+  TRARGS="'[:lower:]' '[:upper:]'"
 else
   { echo "configure: error: "Can\'t find method to covert from upper to lower case with tr"" 1>&2; exit 1; }
 fi
diff --git a/src/configure.in b/src/configure.in
index 0051179a0e..5b279e8669 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -319,13 +319,13 @@ AC_PATH_PROG(ipcrm, ipcrm)
 AC_PATH_PROGS(TR, trbsd tr, NOT_FOUND)
 
 dnl Check tr flags to convert from lower to upper case
-TRSTRINGS=`echo ABCdef | $TR '[[a-z]]' '[[A-Z]]' 2>/dev/null | grep ABCDEF`
-TRCLASS=`echo ABCdef | $TR '[[:lower:]]' '[[:upper:]]' 2>/dev/null | grep ABCDEF`
+TRSTRINGS="`echo ABCdef | $TR '[[a-z]]' '[[A-Z]]' 2>/dev/null | grep ABCDEF`"
+TRCLASS="`echo ABCdef | $TR '[[:lower:]]' '[[:upper:]]' 2>/dev/null | grep ABCDEF`"
 
 if test "$TRSTRINGS" = "ABCDEF"; then
   TRARGS="'[[a-z]]' '[[A-Z]]'"
 elif test "$TRCLASS" = "ABCDEF"; then
-  TRARGS="\"[[:lower:]]\" \"[[:upper:]]\""
+  TRARGS="'[[:lower:]]' '[[:upper:]]'"
 else
   AC_MSG_ERROR("Can\'t find method to covert from upper to lower case with tr")
 fi