diff --git a/ChangeLog b/ChangeLog
index 7ee5b5a75d..2057e02b25 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun May 18 16:42:08 2014  Tanaka Akira  <akr@fsij.org>
+
+	* test/ruby/test_m17n_comb.rb (test_str_crypt): Use Etc.confstr to
+	  detect the glibc version.
+	  libc.so is not an executable on Debian GNU/kFreeBSD 7.0 (wheezy).
+
 Sun May 18 12:15:54 2014  Jonathan Mukai-Heidt  <johnnymukai@gmail.com>
 
 	* io.c (argf_each_line, argf_inplace_mode_set): [DOC] Update ARGF
diff --git a/test/ruby/test_m17n_comb.rb b/test/ruby/test_m17n_comb.rb
index ee43c746f8..8258f422a1 100644
--- a/test/ruby/test_m17n_comb.rb
+++ b/test/ruby/test_m17n_comb.rb
@@ -1,4 +1,5 @@
 require 'test/unit'
+require 'etc'
 require_relative 'allpairs'
 
 class TestM17NComb < Test::Unit::TestCase
@@ -724,12 +725,11 @@ class TestM17NComb < Test::Unit::TestCase
   end
 
   def test_str_crypt
-    begin
-      # glibc 2.16 or later denies salt contained other than [0-9A-Za-z./] #7312
-      glibcpath = `ldd #{RbConfig.ruby}`[/\S+\/libc.so\S+/]
-      glibcver = `#{glibcpath}`[/\AGNU C Library.*version ([0-9.]+)/, 1].split('.').map(&:to_i)
-      strict_crypt = (glibcver <=> [2, 16]) > -1
-    rescue
+    strict_crypt = nil
+    # glibc 2.16 or later denies salt contained other than [0-9A-Za-z./] #7312
+    if defined? Etc::Etc::CS_GNU_LIBC_VERSION
+      glibcver = Etc.confstr(Etc::CS_GNU_LIBC_VERSION).scan(/\d+/).map(&:to_i)
+      strict_crypt = (glibcver <=> [2, 16]) >= 0
     end
 
     combination(STRINGS, STRINGS) {|str, salt|