diff --git a/configure b/configure
index b493aa8d89..d215816d7a 100644
--- a/configure
+++ b/configure
@@ -3760,6 +3760,10 @@ cat >> confdefs.h <<EOF
 #define RUBY_LIB "${prefix}/lib/ruby"
 EOF
 
+cat >> confdefs.h <<EOF
+#define RUBY_SITE_LIB "${prefix}/lib/site_ruby"
+EOF
+
 
 if test "$fat_binary" = yes ; then
     arch="fat-${host_os}"
@@ -3769,8 +3773,17 @@ if test "$fat_binary" = yes ; then
 EOF
 
 
+    cat >> confdefs.h <<EOF
+#define RUBY_SITE_THIN_ARCHLIB "${prefix}/lib/site_ruby/" __ARCHITECTURE__ "-${host_os}" 
+EOF
+
+
     cat >> confdefs.h <<EOF
 #define RUBY_ARCHLIB "${prefix}/lib/ruby/${arch}"
+EOF
+
+    cat >> confdefs.h <<EOF
+#define RUBY_SITE_ARCHLIB "${prefix}/lib/site_ruby/${arch}"
 EOF
 
     cat >> confdefs.h <<EOF
@@ -3781,6 +3794,10 @@ else
     arch="${host_cpu}-${host_os}"
     cat >> confdefs.h <<EOF
 #define RUBY_ARCHLIB "${prefix}/lib/ruby/${arch}"
+EOF
+
+    cat >> confdefs.h <<EOF
+#define RUBY_SITE_ARCHLIB "${prefix}/lib/site_ruby/${arch}"
 EOF
 
     cat >> confdefs.h <<EOF
diff --git a/configure.in b/configure.in
index a6749dd952..f522e6e581 100644
--- a/configure.in
+++ b/configure.in
@@ -453,6 +453,7 @@ if test "$fat_binary" = yes ; then
 fi
 
 AC_DEFINE_UNQUOTED(RUBY_LIB, "${prefix}/lib/ruby")
+AC_DEFINE_UNQUOTED(RUBY_SITE_LIB, "${prefix}/lib/site_ruby")
 AC_SUBST(arch)dnl
 
 if test "$fat_binary" = yes ; then
@@ -461,11 +462,16 @@ if test "$fat_binary" = yes ; then
     AC_DEFINE_UNQUOTED(RUBY_THIN_ARCHLIB,
                  "${prefix}/lib/ruby/" __ARCHITECTURE__ "-${host_os}" )
 
+    AC_DEFINE_UNQUOTED(RUBY_SITE_THIN_ARCHLIB,
+                 "${prefix}/lib/site_ruby/" __ARCHITECTURE__ "-${host_os}" )
+
     AC_DEFINE_UNQUOTED(RUBY_ARCHLIB, "${prefix}/lib/ruby/${arch}")
+    AC_DEFINE_UNQUOTED(RUBY_SITE_ARCHLIB, "${prefix}/lib/site_ruby/${arch}")
     AC_DEFINE_UNQUOTED(RUBY_PLATFORM,  __ARCHITECTURE__ "-${host_os}" )
 else
     arch="${host_cpu}-${host_os}"
     AC_DEFINE_UNQUOTED(RUBY_ARCHLIB, "${prefix}/lib/ruby/${arch}")
+    AC_DEFINE_UNQUOTED(RUBY_SITE_ARCHLIB, "${prefix}/lib/site_ruby/${arch}")
     AC_DEFINE_UNQUOTED(RUBY_PLATFORM, "${arch}")
 fi
 
diff --git a/ruby.c b/ruby.c
index 6983791336..44200ab87d 100644
--- a/ruby.c
+++ b/ruby.c
@@ -703,6 +703,16 @@ ruby_prog_init()
     addpath(RUBY_THIN_ARCHLIB);
 #endif
 
+#ifdef RUBY_SITE_LIB
+    addpath(RUBY_SITE_LIB);
+#endif
+#ifdef RUBY_SITE_ARCHLIB
+    addpath(RUBY_SITE_ARCHLIB);
+#endif
+#ifdef RUBY_SITE_THIN_ARCHLIB
+    addpath(RUBY_SITE_THIN_ARCHLIB);
+#endif
+
     if (rb_safe_level() == 0) {
 	addpath(getenv("RUBYLIB"));
     }