diff --git a/Makefile.rules b/Makefile.rules
index 59d8440..66d90f1 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -522,11 +522,13 @@
   # Building universal cannot compute dependencies automatically.
   DISABLE_AUTO_DEPENDENCIES=1
 else
-  ifeq ($(ARCH),x86_64)
-    CompileCommonOpts += -m64
-  else
-    ifeq ($(ARCH),x86)
-      CompileCommonOpts += -m32
+  ifeq ($(OS),Darwin)
+    ifeq ($(ARCH),x86_64)
+      CompileCommonOpts += -m64
+    else
+      ifeq ($(ARCH),x86)
+        CompileCommonOpts += -m32
+      endif
     endif
   endif
 endif
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 1ef8536..d6c89e3 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -233,13 +233,6 @@
   AC_MSG_WARN([Configuring LLVM for an unknown target archicture])
 fi
 
-if test "$llvm_cv_os_type" = "Linux" -a "$llvm_cv_target_arch" = "x86_64" ; then
-  AC_IS_LINUX_MIXED
-  if test "$llvm_cv_linux_mixed" = "yes"; then
-    llvm_cv_target_arch="x86"
-  fi
-fi
-
 dnl Define a substitution, ARCH, for the target architecture
 AC_SUBST(ARCH,$llvm_cv_target_arch)
 
diff --git a/autoconf/m4/linux_mixed_64_32.m4 b/autoconf/m4/linux_mixed_64_32.m4
deleted file mode 100644
index 7c781ac..0000000
--- a/autoconf/m4/linux_mixed_64_32.m4
+++ /dev/null
@@ -1,17 +0,0 @@
-#
-# Some Linux machines run a 64-bit kernel with a 32-bit userspace. 'uname -m'
-# shows these at x86_64, so in that case, ask the system 'gcc' what it thinks.
-#
-AC_DEFUN([AC_IS_LINUX_MIXED],
-[AC_CACHE_CHECK(for 32-bit userspace on 64-bit system,llvm_cv_linux_mixed,
-[ AC_LANG_PUSH([C])
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
-      [[#ifndef __x86_64__
-       error: Not x86-64 even if uname says so!
-      #endif
-      ]])],
-      [llvm_cv_linux_mixed=no],
-      [llvm_cv_linux_mixed=yes])
-  AC_LANG_POP([C])
-])
-])
diff --git a/configure b/configure
index d6e6758..60ee5c3 100755
--- a/configure
+++ b/configure
@@ -812,6 +812,8 @@
 NOLINKALL
 LLVM_ON_UNIX
 LLVM_ON_WIN32
+ARCH
+ENDIAN
 CC
 CFLAGS
 LDFLAGS
@@ -819,8 +821,6 @@
 ac_ct_CC
 EXEEXT
 OBJEXT
-ARCH
-ENDIAN
 CPP
 GREP
 EGREP
@@ -2393,8 +2393,10 @@
 echo "$as_me: WARNING: Configuring LLVM for an unknown target archicture" >&2;}
 fi
 
-if test "$llvm_cv_os_type" = "Linux" -a "$llvm_cv_target_arch" = "x86_64" ; then
-  ac_ext=c
+ARCH=$llvm_cv_target_arch
+
+
+ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
@@ -3395,97 +3397,6 @@
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
-{ echo "$as_me:$LINENO: checking for 32-bit userspace on 64-bit system" >&5
-echo $ECHO_N "checking for 32-bit userspace on 64-bit system... $ECHO_C" >&6; }
-if test "${llvm_cv_linux_mixed+set}" = set; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-   ac_ext=c
-ac_cpp='$CPP $CPPFLAGS'
-ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
-ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
-ac_compiler_gnu=$ac_cv_c_compiler_gnu
-
-  cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-#ifndef __x86_64__
-       error: Not x86-64 even if uname says so!
-      #endif
-
-int
-main ()
-{
-
-  ;
-  return 0;
-}
-_ACEOF
-rm -f conftest.$ac_objext
-if { (ac_try="$ac_compile"
-case "(($ac_try" in
-  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
-  *) ac_try_echo=$ac_try;;
-esac
-eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
-  (eval "$ac_compile") 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } &&
-	 { ac_try='test -z "$ac_c_werror_flag" || test ! -s conftest.err'
-  { (case "(($ac_try" in
-  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
-  *) ac_try_echo=$ac_try;;
-esac
-eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
-  (eval "$ac_try") 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; } &&
-	 { ac_try='test -s conftest.$ac_objext'
-  { (case "(($ac_try" in
-  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
-  *) ac_try_echo=$ac_try;;
-esac
-eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
-  (eval "$ac_try") 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  llvm_cv_linux_mixed=no
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-	llvm_cv_linux_mixed=yes
-fi
-
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-  ac_ext=c
-ac_cpp='$CPP $CPPFLAGS'
-ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
-ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
-ac_compiler_gnu=$ac_cv_c_compiler_gnu
-
-
-fi
-{ echo "$as_me:$LINENO: result: $llvm_cv_linux_mixed" >&5
-echo "${ECHO_T}$llvm_cv_linux_mixed" >&6; }
-
-  if test "$llvm_cv_linux_mixed" = "yes"; then
-    llvm_cv_target_arch="x86"
-  fi
-fi
-
-ARCH=$llvm_cv_target_arch
-
-
 ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
@@ -10633,7 +10544,7 @@
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 10636 "configure"
+#line 10547 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -12777,7 +12688,7 @@
   ;;
 *-*-irix6*)
   # Find out which ABI we are using.
-  echo '#line 12780 "configure"' > conftest.$ac_ext
+  echo '#line 12691 "configure"' > conftest.$ac_ext
   if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   (eval $ac_compile) 2>&5
   ac_status=$?
@@ -14495,11 +14406,11 @@
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:14498: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:14409: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:14502: \$? = $ac_status" >&5
+   echo "$as_me:14413: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -14763,11 +14674,11 @@
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:14766: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:14677: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:14770: \$? = $ac_status" >&5
+   echo "$as_me:14681: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -14867,11 +14778,11 @@
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:14870: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:14781: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:14874: \$? = $ac_status" >&5
+   echo "$as_me:14785: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -17319,7 +17230,7 @@
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 17322 "configure"
+#line 17233 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -17419,7 +17330,7 @@
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 17422 "configure"
+#line 17333 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -19787,11 +19698,11 @@
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:19790: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:19701: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:19794: \$? = $ac_status" >&5
+   echo "$as_me:19705: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -19891,11 +19802,11 @@
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:19894: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:19805: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:19898: \$? = $ac_status" >&5
+   echo "$as_me:19809: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -21461,11 +21372,11 @@
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:21464: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:21375: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:21468: \$? = $ac_status" >&5
+   echo "$as_me:21379: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -21565,11 +21476,11 @@
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:21568: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:21479: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:21572: \$? = $ac_status" >&5
+   echo "$as_me:21483: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -23800,11 +23711,11 @@
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:23803: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:23714: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:23807: \$? = $ac_status" >&5
+   echo "$as_me:23718: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -24068,11 +23979,11 @@
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:24071: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:23982: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>conftest.err)
    ac_status=$?
    cat conftest.err >&5
-   echo "$as_me:24075: \$? = $ac_status" >&5
+   echo "$as_me:23986: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s "$ac_outfile"; then
      # The compiler can only warn and ignore the option if not recognized
      # So say no if there are warnings other than the usual output.
@@ -24172,11 +24083,11 @@
    -e 's:.*FLAGS}\{0,1\} :&$lt_compiler_flag :; t' \
    -e 's: [^ ]*conftest\.: $lt_compiler_flag&:; t' \
    -e 's:$: $lt_compiler_flag:'`
-   (eval echo "\"\$as_me:24175: $lt_compile\"" >&5)
+   (eval echo "\"\$as_me:24086: $lt_compile\"" >&5)
    (eval "$lt_compile" 2>out/conftest.err)
    ac_status=$?
    cat out/conftest.err >&5
-   echo "$as_me:24179: \$? = $ac_status" >&5
+   echo "$as_me:24090: \$? = $ac_status" >&5
    if (exit $ac_status) && test -s out/conftest2.$ac_objext
    then
      # The compiler can only warn and ignore the option if not recognized
@@ -34804,6 +34715,8 @@
 NOLINKALL!$NOLINKALL$ac_delim
 LLVM_ON_UNIX!$LLVM_ON_UNIX$ac_delim
 LLVM_ON_WIN32!$LLVM_ON_WIN32$ac_delim
+ARCH!$ARCH$ac_delim
+ENDIAN!$ENDIAN$ac_delim
 CC!$CC$ac_delim
 CFLAGS!$CFLAGS$ac_delim
 LDFLAGS!$LDFLAGS$ac_delim
@@ -34811,8 +34724,6 @@
 ac_ct_CC!$ac_ct_CC$ac_delim
 EXEEXT!$EXEEXT$ac_delim
 OBJEXT!$OBJEXT$ac_delim
-ARCH!$ARCH$ac_delim
-ENDIAN!$ENDIAN$ac_delim
 CPP!$CPP$ac_delim
 GREP!$GREP$ac_delim
 EGREP!$EGREP$ac_delim