diff --git a/ChangeLog b/ChangeLog
index 5f045d0f56..2025bc7f1e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,7 @@
-Mon Feb 11 13:15:11 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Mon Feb 11 13:17:20 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (rubysitearchprefix): sitearchdir and vendorarchdir
+	  should use sitearch, not arch.  [ruby-dev:46964] [Bug #7823]
 
 	* win32/Makefile.sub (config.status): site and vendor directories
 	  should use sitearch, not arch.  [ruby-dev:46964] [Bug #7823]
diff --git a/configure.in b/configure.in
index b77b6fd894..428dc8492b 100644
--- a/configure.in
+++ b/configure.in
@@ -3163,10 +3163,10 @@ AC_ARG_ENABLE(multiarch,
 	      AS_HELP_STRING([--enable-multiarch], [enable multiarch compatible directories]),
 	      [multiarch=], [unset multiarch])
 
-archlibdir='${libdir}'${multiarch+'/${arch}'}
-sitearchlibdir='${libdir}'${multiarch+'/${sitearch}'}
-archincludedir='${includedir}'${multiarch+'/${arch}'}
-sitearchincludedir='${includedir}'${multiarch+'/${sitearch}'}
+archlibdir='${libdir}/${arch}'
+sitearchlibdir='${libdir}/${sitearch}'
+archincludedir='${includedir}/${arch}'
+sitearchincludedir='${includedir}/${sitearch}'
 
 shvar_to_cpp() {
     local var="$1" val="$2"
@@ -3190,6 +3190,7 @@ shvar_to_cpp() {
 	    -e 's/\${rubylibdir}/"RUBY_LIB"/g' \
 	    -e 's/\${rubylibprefix}/"RUBY_LIB_PREFIX"/g' \
 	    -e 's/\${rubyarchprefix}/"RUBY_ARCH_PREFIX_FOR(arch)"/g' \
+	    -e 's/\${rubysitearchprefix}/"RUBY_SITEARCH_PREFIX_FOR(arch)"/g' \
 	    -e 's/\${exec_prefix}/"RUBY_EXEC_PREFIX"/g' \
 	    -e 's|^\"NONE/|RUBY_EXEC_PREFIX\"/|' \
 	    -e 's|^\"NONE\"|\"'"${prefix}"'\"|' \
@@ -3216,6 +3217,13 @@ AC_ARG_WITH(rubyarchprefix,
 	    [rubyarchprefix="$withval"])
 AC_SUBST(rubyarchprefix)
 
+rubysitearchprefix=${multiarch+'${sitearchlibdir}/${RUBY_BASE_NAME}'}${multiarch-'${rubylibprefix}/${sitearch}'}
+AC_ARG_WITH(rubysitearchprefix,
+	    AS_HELP_STRING([--with-rubysitearchprefix=DIR],
+			   [prefix for architecture dependent site libraries [[RUBYLIBPREFIX/SITEARCH]]]),
+	    [rubysitearchprefix="$withval"])
+AC_SUBST(rubysitearchprefix)
+
 RI_BASE_NAME=`echo ${RUBY_BASE_NAME} | sed 's/ruby/ri/'`
 ridir='${datarootdir}/${RI_BASE_NAME}'
 AC_ARG_WITH(ridir,
@@ -3261,7 +3269,7 @@ AC_ARG_WITH(sitearchdir,
 	    AS_HELP_STRING([--with-sitearchdir=DIR],
 			   [architecture dependent site libraries in DIR [[SITEDIR/SITEARCH]], "no" to disable site directory]),
             [sitearchdir=$withval],
-            [sitearchdir=${multiarch+'${rubyarchprefix}/site_ruby/${ruby_version}'}${multiarch-'${sitelibdir}/${sitearch}'}])
+            [sitearchdir=${multiarch+'${rubysitearchprefix}/site_ruby/${ruby_version}'}${multiarch-'${sitelibdir}/${sitearch}'}])
 
 AC_ARG_WITH(vendordir,
 	    AS_HELP_STRING([--with-vendordir=DIR], [vendor libraries in DIR [[RUBY_LIB_PREFIX/vendor_ruby]], "no" to disable vendor directory]),
@@ -3273,7 +3281,7 @@ AC_ARG_WITH(vendorarchdir,
 	    AS_HELP_STRING([--with-vendorarchdir=DIR],
 			   [architecture dependent vendor libraries in DIR [[VENDORDIR/SITEARCH]], "no" to disable vendor directory]),
             [vendorarchdir=$withval],
-            [vendorarchdir=${multiarch+'${rubyarchprefix}/vendor_ruby/${ruby_version}'}${multiarch-'${vendorlibdir}/${sitearch}'}])
+            [vendorarchdir=${multiarch+'${rubysitearchprefix}/vendor_ruby/${ruby_version}'}${multiarch-'${vendorlibdir}/${sitearch}'}])
 
 if test "${LOAD_RELATIVE+set}"; then
     AC_DEFINE_UNQUOTED(LOAD_RELATIVE, $LOAD_RELATIVE)
@@ -3283,6 +3291,7 @@ else
 fi
 shvar_to_cpp RUBY_LIB_PREFIX "${rubylibprefix}"
 shvar_to_cpp RUBY_ARCH_PREFIX_FOR "${rubyarchprefix}"
+shvar_to_cpp RUBY_SITEARCH_PREFIX_FOR "${rubysitearchprefix}"
 shvar_to_cpp RIDIR "${ridir}"
 
 if test ${RUBY_LIB_VERSION_STYLE+set}; then
@@ -3293,6 +3302,7 @@ fi
 AC_DEFINE_UNQUOTED(RUBY_EXEC_PREFIX, ${RUBY_EXEC_PREFIX})
 AC_DEFINE_UNQUOTED(RUBY_LIB_PREFIX, ${RUBY_LIB_PREFIX} !<verconf>!)
 AC_DEFINE_UNQUOTED(RUBY_ARCH_PREFIX_FOR(arch), ${RUBY_ARCH_PREFIX_FOR} !<verconf>!)
+AC_DEFINE_UNQUOTED(RUBY_SITEARCH_PREFIX_FOR(arch), ${RUBY_SITEARCH_PREFIX_FOR} !<verconf>!)
 
 shvar_to_cpp RUBY_LIB "${rubylibdir}"
 if test "x${RUBY_LIB}" != 'xRUBY_LIB_PREFIX"/"RUBY_LIB_VERSION'; then
diff --git a/template/ruby.pc.in b/template/ruby.pc.in
index 7ffd2d43d0..65a3f79857 100644
--- a/template/ruby.pc.in
+++ b/template/ruby.pc.in
@@ -31,6 +31,7 @@ sitearchincludedir=@sitearchincludedir@
 ruby=${bindir}/${RUBY_INSTALL_NAME}@EXEEXT@
 rubylibprefix=@rubylibprefix@
 rubyarchprefix=@rubyarchprefix@
+rubysitearchprefix=@rubysitearchprefix@
 rubylibdir=@rubylibdir@
 vendordir=@vendordir@
 sitedir=@sitedir@
diff --git a/test/test_rbconfig.rb b/test/test_rbconfig.rb
index b241a926fc..49d65e9d06 100644
--- a/test/test_rbconfig.rb
+++ b/test/test_rbconfig.rb
@@ -27,7 +27,7 @@ class TestRbConfig < Test::Unit::TestCase
     bug7823 = '[ruby-dev:46964] [Bug #7823]'
     RbConfig::MAKEFILE_CONFIG.each do |key, val|
       next unless /\Asite.*arch.*dir\z/ =~ key
-      assert_match(/\$\(sitearch|\$\(rubyarchprefix\)/, val, "#{key} #{bug7823}")
+      assert_match(/\$\(sitearch|\$\(rubysitearchprefix\)/, val, "#{key} #{bug7823}")
     end
   end
 
@@ -35,7 +35,7 @@ class TestRbConfig < Test::Unit::TestCase
     bug7823 = '[ruby-dev:46964] [Bug #7823]'
     RbConfig::MAKEFILE_CONFIG.each do |key, val|
       next unless /\Avendor.*arch.*dir\z/ =~ key
-      assert_match(/\$\(sitearch|\$\(rubyarchprefix\)/, val, "#{key} #{bug7823}")
+      assert_match(/\$\(sitearch|\$\(rubysitearchprefix\)/, val, "#{key} #{bug7823}")
     end
   end
 end