diff --git a/src/configure b/src/configure
index 561daf8d78..29bb4e32f6 100755
--- a/src/configure
+++ b/src/configure
@@ -311,9 +311,10 @@ ac_includes_default="\
 #endif"
 
 ac_subdirs_all="$ac_subdirs_all foreign/gcc/libffi"
+ac_subdirs_all="$ac_subdirs_all llvm/llvm"
 ac_subdirs_all="$ac_subdirs_all wxcommon/jpeg"
 ac_subdirs_all="$ac_subdirs_all wxxt/src/x/wbuild"
-ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT CPP EGREP CXX CXXFLAGS ac_ct_CXX CXXCPP RANLIB ac_ct_RANLIB PERL X_CFLAGS X_PRE_LIBS X_LIBS X_EXTRA_LIBS PREFLAGS COMPFLAGS PROFFLAGS SED AS AR STATIC_AR ARFLAGS WBUILD CC_FOR_BUILD REZ MZLINKER PLAIN_CC x_includes x_libraries OPTIONS MZOPTIONS CGCOPTIONS GC2OPTIONS MROPTIONS GCDIR MZBINTARGET MZINSTALLTARGET EXTRA_GMP_OBJ OSX NOT_OSX FRAMEWORK_INSTALL_DIR MREDLINKER LIBSFX WXLIBS WXVARIANT ICP MRLIBINSTALL LIBFINISH MAKE_MRED MAKE_MRED3M MAKE_MREDINSTALL MAKE_MREDINSTALL3M MAKE_WBUILD MAKE_COPYTREE MAKE_FINISH WXPRECOMP USE_WXPRECOMP INCLUDEDEP WX_MMD_FLAG JPEG_A JPEG_INC ZLIB_A ZLIB_INC PNG_A OSKHOME EXTRA_OSK_LIBS FOREIGN_OBJSLIB_IF_USED FOREIGN_LIB_IF_USED FOREIGN_OBJSLIB FOREIGN_CONVENIENCE FOREIGNTARGET LTO LTA subdirs LIBOBJS LTLIBOBJS'
+ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT CPP EGREP CXX CXXFLAGS ac_ct_CXX CXXCPP RANLIB ac_ct_RANLIB PERL X_CFLAGS X_PRE_LIBS X_LIBS X_EXTRA_LIBS PREFLAGS COMPFLAGS PROFFLAGS SED AS AR STATIC_AR ARFLAGS WBUILD CC_FOR_BUILD REZ MZLINKER PLAIN_CC x_includes x_libraries OPTIONS MZOPTIONS CGCOPTIONS GC2OPTIONS MROPTIONS GCDIR MZBINTARGET MZINSTALLTARGET EXTRA_GMP_OBJ OSX NOT_OSX FRAMEWORK_INSTALL_DIR MREDLINKER LIBSFX WXLIBS WXVARIANT ICP MRLIBINSTALL LIBFINISH MAKE_MRED MAKE_MRED3M MAKE_MREDINSTALL MAKE_MREDINSTALL3M MAKE_WBUILD MAKE_COPYTREE MAKE_FINISH WXPRECOMP USE_WXPRECOMP INCLUDEDEP WX_MMD_FLAG JPEG_A JPEG_INC ZLIB_A ZLIB_INC PNG_A OSKHOME EXTRA_OSK_LIBS FOREIGN_OBJSLIB_IF_USED FOREIGN_LIB_IF_USED FOREIGN_OBJSLIB FOREIGN_CONVENIENCE FOREIGNTARGET LLVMTARGET LTO LTA subdirs LIBOBJS LTLIBOBJS'
 ac_subst_files=''
 
 # Initialize some variables set by options.
@@ -871,6 +872,7 @@ Optional Features:
   --enable-shared         create shared libraries
   --enable-dynlib         same as --enable-shared
   --enable-foreign        compile foreign support (enabled by default)
+  --enable-llvm           compile llvm support (disabled by default)
   --enable-sgc            use Senora GC instead of the Boehm GC
   --enable-sgcdebug       use Senora GC for debugging
   --enable-account        3m: use memory-accounting GC (enabled by default)
@@ -1405,6 +1407,13 @@ if test "${enable_foreign+set}" = set; then
 else
   enable_foreign=yes
 fi;
+# Check whether --enable-llvm or --disable-llvm was given.
+if test "${enable_llvm+set}" = set; then
+  enableval="$enable_llvm"
+
+else
+  enable_llvm=no
+fi;
 
 # Check whether --enable-sgc or --disable-sgc was given.
 if test "${enable_sgc+set}" = set; then
@@ -10969,6 +10978,8 @@ LIBS="$LIBS $EXTRALIBS"
 
 
 
+
+
 
 
 
@@ -11036,6 +11047,23 @@ else
   MZOPTIONS="$MZOPTIONS -DDONT_USE_FOREIGN"
 fi
 
+LLVMTARGET=
+if test -d "${srcdir}/llvm" && test "${enable_llvm}" = "yes" ; then
+
+
+subdirs="$subdirs llvm/llvm "
+
+  makefiles="$makefiles llvm/Makefile"
+  LLVMTARGET="llvm-stuff"
+  # Again, this changes arguments that are passed to *all* sub-configure
+  # invocations, which might be a problem.  Hopefully nobody else uses
+  # "--enable-targets" and if someone else uses "--enable-optimized" we might
+  # as well just go with it...
+  ac_configure_args="$ac_configure_args --enable-optimized --enable-targets=host-only"
+else
+  LLVMTARGET="llvm-nothing"
+fi
+
 if test "${enable_mred}" = "yes" ; then
   if test "${enable_quartz}" = "yes" ; then
     mk_needed_dir wxmac
@@ -11817,6 +11845,7 @@ s,@FOREIGN_LIB_IF_USED@,$FOREIGN_LIB_IF_USED,;t t
 s,@FOREIGN_OBJSLIB@,$FOREIGN_OBJSLIB,;t t
 s,@FOREIGN_CONVENIENCE@,$FOREIGN_CONVENIENCE,;t t
 s,@FOREIGNTARGET@,$FOREIGNTARGET,;t t
+s,@LLVMTARGET@,$LLVMTARGET,;t t
 s,@LTO@,$LTO,;t t
 s,@LTA@,$LTA,;t t
 s,@subdirs@,$subdirs,;t t
diff --git a/src/mzscheme/Makefile.in b/src/mzscheme/Makefile.in
index c453eef8f0..405c421f25 100644
--- a/src/mzscheme/Makefile.in
+++ b/src/mzscheme/Makefile.in
@@ -30,11 +30,14 @@ FOREIGN_OBJSLIB = @FOREIGN_OBJSLIB@
 # The foreign build always uses libtool, so that's why we use .la instead of @LTA@
 #  in FOREIGN_LIB.
 
+LLVM_DIR = ../llvm
+
 ################################################################################
 
 bin: 
 	$(MAKE) g-c
 	$(MAKE) @FOREIGNTARGET@
+	$(MAKE) @LLVMTARGET@
 	$(MAKE) @MZBINTARGET@
 
 normal-bin:
@@ -93,6 +96,13 @@ foreign-stuff:
 foreign-nothing:
 	echo no foreign
 
+# llvm
+llvm-stuff:
+	cd $(LLVM_DIR); $(MAKE) all
+
+llvm-nothing:
+	echo no llvm
+
 mzlibrary:
 	cd src; $(MAKE) all 
 	$(MAKE) libmzscheme.@LIBSFX@
@@ -232,6 +242,7 @@ clean@NOT_OSX@:
 	cd src; $(MAKE) clean
 	cd dynsrc; $(MAKE) clean
 	if [ ! -d ../foreign ] ; then cd ../foreign ; $(MAKE) clean ; fi
+	if [ ! -d ../llvm    ] ; then cd ../llvm    ; $(MAKE) clean ; fi
 
 clean@OSX@:
 	rm -rf PLT_MzScheme.framework
diff --git a/src/mzscheme/configure.ac b/src/mzscheme/configure.ac
index 66f3a80e5c..44a439f776 100644
--- a/src/mzscheme/configure.ac
+++ b/src/mzscheme/configure.ac
@@ -37,6 +37,7 @@ AC_ARG_ENABLE(shared, [  --enable-shared         create shared libraries])
 AC_ARG_ENABLE(dynlib, [  --enable-dynlib         same as --enable-shared])
 
 AC_ARG_ENABLE(foreign, [  --enable-foreign        compile foreign support (enabled by default)], , enable_foreign=yes)
+AC_ARG_ENABLE(llvm,    [  --enable-llvm           compile llvm support (disabled by default)], , enable_llvm=no)
 
 AC_ARG_ENABLE(sgc, [  --enable-sgc            use Senora GC instead of the Boehm GC])
 AC_ARG_ENABLE(sgcdebug, [  --enable-sgcdebug       use Senora GC for debugging])
@@ -1044,6 +1045,8 @@ AC_SUBST(FOREIGN_OBJSLIB)
 AC_SUBST(FOREIGN_CONVENIENCE)
 AC_SUBST(FOREIGNTARGET)
 
+AC_SUBST(LLVMTARGET)
+
 AC_SUBST(LTO)
 AC_SUBST(LTA)
 
@@ -1084,6 +1087,20 @@ else
   MZOPTIONS="$MZOPTIONS -DDONT_USE_FOREIGN"
 fi
 
+LLVMTARGET=
+if test -d "${srcdir}/llvm" && test "${enable_llvm}" = "yes" ; then
+  AC_CONFIG_SUBDIRS( llvm/llvm )
+  makefiles="$makefiles llvm/Makefile"
+  LLVMTARGET="llvm-stuff"
+  # Again, this changes arguments that are passed to *all* sub-configure
+  # invocations, which might be a problem.  Hopefully nobody else uses
+  # "--enable-targets" and if someone else uses "--enable-optimized" we might
+  # as well just go with it...
+  ac_configure_args="$ac_configure_args --enable-optimized --enable-targets=host-only"
+else
+  LLVMTARGET="llvm-nothing"
+fi
+
 if test "${enable_mred}" = "yes" ; then
   if test "${enable_quartz}" = "yes" ; then
     mk_needed_dir wxmac
diff --git a/src/mzscheme/clean_ac.ss b/src/mzscheme/make-configure
old mode 100644
new mode 100755
similarity index 72%
rename from src/mzscheme/clean_ac.ss
rename to src/mzscheme/make-configure
index bebfbc0aa4..6df7e45b6b
--- a/src/mzscheme/clean_ac.ss
+++ b/src/mzscheme/make-configure
@@ -1,3 +1,17 @@
+#!/bin/sh
+#|
+cd "`dirname \"$0\"`"
+src="configure.ac"
+tgt="../configure"
+if [ ! -e "$src" ]; then echo "abort: did not find $src"; exit 1; fi
+echo "Creating $tgt from $src"
+if [ -e "$tgt" ]; then
+  echo -n "overwriting $tgt, Ctrl-C to abort, enter to continue "; read R;
+fi
+autoconf "$src" | mzscheme -r "$0" > "$tgt"
+chmod +x "$tgt"
+exit 0
+|#
 
 ;; When autoconf produces `configure', it includes many
 ;;  options that do not apply to PLT software. We want to