diff --git a/ChangeLog b/ChangeLog
index 0166e4f2671..a93fa2c46aa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2007-10-01  Paolo Bonzini  <bonzini@gnu.org>
+
+	* Makefile.tpl (AR_FOR_BUILD, AS_FOR_BUILD, CXX_FOR_BUILD,
+	DLLTOOL_FOR_BUILD, GCJ_FOR_BUILD, GFORTRAN_FOR_BUILD,
+	LDFLAGS_FOR_BUILD, LD_FOR_BUILD, NM_FOR_BUILD, RANLIB_FOR_BUILD,
+	WINDMC_FOR_BUILD, WINDRES_FOR_BUILD): Use autoconf substitutions.
+	* configure.ac: Default them to host tools for $host = $build.
+	Subst them.
+
+	* configure: Regenerate.
+	* Makefile.in: Regenerate.
+
 2006-09-24  Peter Bergner <bergner@vnet.ibm.com>
 
 	* MAINTAINERS (Register allocation reviewer): Add myself.
diff --git a/Makefile.in b/Makefile.in
index 4f33f9f8ba9..7807e9ea191 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -251,10 +251,21 @@ PWD_COMMAND = $${PWDCMD-pwd}
 
 # compilers to use to create programs which must be run in the build
 # environment.
+AR_FOR_BUILD = @AR_FOR_BUILD@
+AS_FOR_BUILD = @AS_FOR_BUILD@
 CC_FOR_BUILD = @CC_FOR_BUILD@
 CFLAGS_FOR_BUILD = @CFLAGS_FOR_BUILD@
-
-CXX_FOR_BUILD = $(CXX)
+CXXFLAGS_FOR_BUILD = @CXXFLAGS_FOR_BUILD@
+CXX_FOR_BUILD = @CXX_FOR_BUILD@
+DLLTOOL_FOR_BUILD = @DLLTOOL_FOR_BUILD@
+GCJ_FOR_BUILD = @GCJ_FOR_BUILD@
+GFORTRAN_FOR_BUILD = @GFORTRAN_FOR_BUILD@
+LDFLAGS_FOR_BUILD = @LDFLAGS_FOR_BUILD@
+LD_FOR_BUILD = @LD_FOR_BUILD@
+NM_FOR_BUILD = @NM_FOR_BUILD@
+RANLIB_FOR_BUILD = @RANLIB_FOR_BUILD@
+WINDMC_FOR_BUILD = @WINDMC_FOR_BUILD@
+WINDRES_FOR_BUILD = @WINDRES_FOR_BUILD@
 
 # Special variables passed down in EXTRA_GCC_FLAGS.  They are defined
 # here so that they can be overridden by Makefile fragments.
diff --git a/Makefile.tpl b/Makefile.tpl
index cf979616636..9d23058aa30 100644
--- a/Makefile.tpl
+++ b/Makefile.tpl
@@ -254,10 +254,21 @@ PWD_COMMAND = $${PWDCMD-pwd}
 
 # compilers to use to create programs which must be run in the build
 # environment.
+AR_FOR_BUILD = @AR_FOR_BUILD@
+AS_FOR_BUILD = @AS_FOR_BUILD@
 CC_FOR_BUILD = @CC_FOR_BUILD@
 CFLAGS_FOR_BUILD = @CFLAGS_FOR_BUILD@
-
-CXX_FOR_BUILD = $(CXX)
+CXXFLAGS_FOR_BUILD = @CXXFLAGS_FOR_BUILD@
+CXX_FOR_BUILD = @CXX_FOR_BUILD@
+DLLTOOL_FOR_BUILD = @DLLTOOL_FOR_BUILD@
+GCJ_FOR_BUILD = @GCJ_FOR_BUILD@
+GFORTRAN_FOR_BUILD = @GFORTRAN_FOR_BUILD@
+LDFLAGS_FOR_BUILD = @LDFLAGS_FOR_BUILD@
+LD_FOR_BUILD = @LD_FOR_BUILD@
+NM_FOR_BUILD = @NM_FOR_BUILD@
+RANLIB_FOR_BUILD = @RANLIB_FOR_BUILD@
+WINDMC_FOR_BUILD = @WINDMC_FOR_BUILD@
+WINDRES_FOR_BUILD = @WINDRES_FOR_BUILD@
 
 # Special variables passed down in EXTRA_GCC_FLAGS.  They are defined
 # here so that they can be overridden by Makefile fragments.
diff --git a/configure b/configure
index eca027f19e3..3d4545102f6 100755
--- a/configure
+++ b/configure
@@ -272,7 +272,7 @@ PACKAGE_STRING=
 PACKAGE_BUGREPORT=
 
 ac_unique_file="move-if-change"
-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 build build_cpu build_vendor build_os build_noncanonical host_noncanonical target_noncanonical host host_cpu host_vendor host_os target target_cpu target_vendor target_os INSTALL_PROGRAM INSTALL_SCRIPT INSTALL_DATA LN LN_S TOPLEVEL_CONFIGURE_ARGUMENTS build_libsubdir build_subdir host_subdir target_subdir CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT CXX CXXFLAGS ac_ct_CXX GNATBIND ac_ct_GNATBIND GNATMAKE ac_ct_GNATMAKE do_compare gmplibs gmpinc stage1_languages SYSROOT_CFLAGS_FOR_TARGET DEBUG_PREFIX_CFLAGS_FOR_TARGET RPATH_ENVVAR tooldir build_tooldir CONFIGURE_GDB_TK GDB_TK INSTALL_GDB_TK build_configargs build_configdirs host_configargs configdirs target_configargs CC_FOR_BUILD config_shell YACC BISON M4 LEX FLEX MAKEINFO EXPECT RUNTEST AR AS DLLTOOL LD LIPO NM RANLIB STRIP WINDRES WINDMC OBJCOPY OBJDUMP CFLAGS_FOR_BUILD CC_FOR_TARGET CXX_FOR_TARGET GCC_FOR_TARGET GCJ_FOR_TARGET GFORTRAN_FOR_TARGET AR_FOR_TARGET AS_FOR_TARGET DLLTOOL_FOR_TARGET LD_FOR_TARGET LIPO_FOR_TARGET NM_FOR_TARGET OBJDUMP_FOR_TARGET RANLIB_FOR_TARGET STRIP_FOR_TARGET WINDRES_FOR_TARGET WINDMC_FOR_TARGET RAW_CXX_FOR_TARGET FLAGS_FOR_TARGET COMPILER_AS_FOR_TARGET COMPILER_LD_FOR_TARGET COMPILER_NM_FOR_TARGET MAINTAINER_MODE_TRUE MAINTAINER_MODE_FALSE MAINT stage1_cflags stage1_checking stage2_werror_flag datarootdir docdir pdfdir htmldir 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 build build_cpu build_vendor build_os build_noncanonical host_noncanonical target_noncanonical host host_cpu host_vendor host_os target target_cpu target_vendor target_os INSTALL_PROGRAM INSTALL_SCRIPT INSTALL_DATA LN LN_S TOPLEVEL_CONFIGURE_ARGUMENTS build_libsubdir build_subdir host_subdir target_subdir CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT CXX CXXFLAGS ac_ct_CXX GNATBIND ac_ct_GNATBIND GNATMAKE ac_ct_GNATMAKE do_compare gmplibs gmpinc stage1_languages SYSROOT_CFLAGS_FOR_TARGET DEBUG_PREFIX_CFLAGS_FOR_TARGET RPATH_ENVVAR tooldir build_tooldir CONFIGURE_GDB_TK GDB_TK INSTALL_GDB_TK build_configargs build_configdirs host_configargs configdirs target_configargs AR_FOR_BUILD AS_FOR_BUILD CC_FOR_BUILD CFLAGS_FOR_BUILD CXXFLAGS_FOR_BUILD CXX_FOR_BUILD DLLTOOL_FOR_BUILD GCJ_FOR_BUILD GFORTRAN_FOR_BUILD LDFLAGS_FOR_BUILD LD_FOR_BUILD NM_FOR_BUILD RANLIB_FOR_BUILD WINDMC_FOR_BUILD WINDRES_FOR_BUILD config_shell YACC BISON M4 LEX FLEX MAKEINFO EXPECT RUNTEST AR AS DLLTOOL LD LIPO NM RANLIB STRIP WINDRES WINDMC OBJCOPY OBJDUMP CC_FOR_TARGET CXX_FOR_TARGET GCC_FOR_TARGET GCJ_FOR_TARGET GFORTRAN_FOR_TARGET AR_FOR_TARGET AS_FOR_TARGET DLLTOOL_FOR_TARGET LD_FOR_TARGET LIPO_FOR_TARGET NM_FOR_TARGET OBJDUMP_FOR_TARGET RANLIB_FOR_TARGET STRIP_FOR_TARGET WINDRES_FOR_TARGET WINDMC_FOR_TARGET RAW_CXX_FOR_TARGET FLAGS_FOR_TARGET COMPILER_AS_FOR_TARGET COMPILER_LD_FOR_TARGET COMPILER_NM_FOR_TARGET MAINTAINER_MODE_TRUE MAINTAINER_MODE_FALSE MAINT stage1_cflags stage1_checking stage2_werror_flag datarootdir docdir pdfdir htmldir LIBOBJS LTLIBOBJS'
 ac_subst_files='serialization_dependencies host_makefile_frag target_makefile_frag alphaieee_frag ospace_frag'
 
 # Initialize some variables set by options.
@@ -2806,9 +2806,31 @@ if test -z "${CC}" && test "${build}" = "${host}" ; then
 fi
 
 if test "${build}" != "${host}" ; then
+  AR_FOR_BUILD=${AR_FOR_BUILD-ar}
+  AS_FOR_BUILD=${AS_FOR_BUILD-as}
   CC_FOR_BUILD=${CC_FOR_BUILD-gcc}
+  CXX_FOR_BUILD=${CXX_FOR_BUILD-g++}
+  GCJ_FOR_BUILD=${GCJ_FOR_BUILD-gcj}
+  GFORTRAN_FOR_BUILD=${GFORTRAN_FOR_BUILD-gfortran}
+  DLLTOOL_FOR_BUILD=${DLLTOOL_FOR_BUILD-dlltool}
+  LD_FOR_BUILD=${LD_FOR_BUILD-ld}
+  NM_FOR_BUILD=${NM_FOR_BUILD-nm}
+  RANLIB_FOR_BUILD=${RANLIB_FOR_BUILD-ranlib}
+  WINDRES_FOR_BUILD=${WINDRES_FOR_BUILD-windres}
+  WINDMC_FOR_BUILD=${WINDMC_FOR_BUILD-windmc}
 else
+  AR_FOR_BUILD="\$(AR)"
+  AS_FOR_BUILD="\$(AS)"
   CC_FOR_BUILD="\$(CC)"
+  CXX_FOR_BUILD="\$(CXX)"
+  GCJ_FOR_BUILD="\$(GCJ)"
+  GFORTRAN_FOR_BUILD="\$(GFORTRAN)"
+  DLLTOOL_FOR_BUILD="\$(DLLTOOL)"
+  LD_FOR_BUILD="\$(LD)"
+  NM_FOR_BUILD="\$(NM)"
+  RANLIB_FOR_BUILD="\$(RANLIB)"
+  WINDRES_FOR_BUILD="\$(WINDRES)"
+  WINDMC_FOR_BUILD="\$(WINDMC)"
 fi
 
 ac_ext=c
@@ -5855,6 +5877,8 @@ esac
 # Allow the user to override the flags for
 # our build compiler if desired.
 CFLAGS_FOR_BUILD=${CFLAGS_FOR_BUILD-${CFLAGS}}
+CXXFLAGS_FOR_BUILD=${CXXFLAGS_FOR_BUILD-${CFLAGS}}
+LDFLAGS_FOR_BUILD=${LDFLAGS_FOR_BUILD-${CFLAGS}}
 
 # On Canadian crosses, we'll be searching the right directories for
 # the previously-installed cross compiler, so don't bother to add
@@ -5915,6 +5939,20 @@ done
 
 
 
+
+
+
+
+
+
+
+
+
+
+
+
+
+
 # Generate default definitions for YACC, M4, LEX and other programs that run
 # on the build machine.  These are used if the Makefile can't locate these
 # programs in objdir.
@@ -7922,7 +7960,6 @@ fi
 
 
 
-
 # Target tools.
 
 # Check whether --with-build-time-tools or --without-build-time-tools was given.
@@ -12793,7 +12830,21 @@ s,@build_configdirs@,$build_configdirs,;t t
 s,@host_configargs@,$host_configargs,;t t
 s,@configdirs@,$configdirs,;t t
 s,@target_configargs@,$target_configargs,;t t
+s,@AR_FOR_BUILD@,$AR_FOR_BUILD,;t t
+s,@AS_FOR_BUILD@,$AS_FOR_BUILD,;t t
 s,@CC_FOR_BUILD@,$CC_FOR_BUILD,;t t
+s,@CFLAGS_FOR_BUILD@,$CFLAGS_FOR_BUILD,;t t
+s,@CXXFLAGS_FOR_BUILD@,$CXXFLAGS_FOR_BUILD,;t t
+s,@CXX_FOR_BUILD@,$CXX_FOR_BUILD,;t t
+s,@DLLTOOL_FOR_BUILD@,$DLLTOOL_FOR_BUILD,;t t
+s,@GCJ_FOR_BUILD@,$GCJ_FOR_BUILD,;t t
+s,@GFORTRAN_FOR_BUILD@,$GFORTRAN_FOR_BUILD,;t t
+s,@LDFLAGS_FOR_BUILD@,$LDFLAGS_FOR_BUILD,;t t
+s,@LD_FOR_BUILD@,$LD_FOR_BUILD,;t t
+s,@NM_FOR_BUILD@,$NM_FOR_BUILD,;t t
+s,@RANLIB_FOR_BUILD@,$RANLIB_FOR_BUILD,;t t
+s,@WINDMC_FOR_BUILD@,$WINDMC_FOR_BUILD,;t t
+s,@WINDRES_FOR_BUILD@,$WINDRES_FOR_BUILD,;t t
 s,@config_shell@,$config_shell,;t t
 s,@YACC@,$YACC,;t t
 s,@BISON@,$BISON,;t t
@@ -12815,7 +12866,6 @@ s,@WINDRES@,$WINDRES,;t t
 s,@WINDMC@,$WINDMC,;t t
 s,@OBJCOPY@,$OBJCOPY,;t t
 s,@OBJDUMP@,$OBJDUMP,;t t
-s,@CFLAGS_FOR_BUILD@,$CFLAGS_FOR_BUILD,;t t
 s,@CC_FOR_TARGET@,$CC_FOR_TARGET,;t t
 s,@CXX_FOR_TARGET@,$CXX_FOR_TARGET,;t t
 s,@GCC_FOR_TARGET@,$GCC_FOR_TARGET,;t t
diff --git a/configure.ac b/configure.ac
index 1496347d86a..e1cce0746e2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -41,6 +41,7 @@ AC_CANONICAL_SYSTEM
 AC_ARG_PROGRAM
 
 m4_pattern_allow([^AS_FOR_TARGET$])dnl
+m4_pattern_allow([^AS_FOR_BUILD$])dnl
 
 # Get 'install' or 'install-sh' and its variants.
 AC_PROG_INSTALL
@@ -1082,9 +1083,31 @@ if test -z "${CC}" && test "${build}" = "${host}" ; then
 fi
 
 if test "${build}" != "${host}" ; then
+  AR_FOR_BUILD=${AR_FOR_BUILD-ar}
+  AS_FOR_BUILD=${AS_FOR_BUILD-as}
   CC_FOR_BUILD=${CC_FOR_BUILD-gcc}
+  CXX_FOR_BUILD=${CXX_FOR_BUILD-g++}
+  GCJ_FOR_BUILD=${GCJ_FOR_BUILD-gcj}
+  GFORTRAN_FOR_BUILD=${GFORTRAN_FOR_BUILD-gfortran}
+  DLLTOOL_FOR_BUILD=${DLLTOOL_FOR_BUILD-dlltool}
+  LD_FOR_BUILD=${LD_FOR_BUILD-ld}
+  NM_FOR_BUILD=${NM_FOR_BUILD-nm}
+  RANLIB_FOR_BUILD=${RANLIB_FOR_BUILD-ranlib}
+  WINDRES_FOR_BUILD=${WINDRES_FOR_BUILD-windres}
+  WINDMC_FOR_BUILD=${WINDMC_FOR_BUILD-windmc}
 else
+  AR_FOR_BUILD="\$(AR)"
+  AS_FOR_BUILD="\$(AS)"
   CC_FOR_BUILD="\$(CC)"
+  CXX_FOR_BUILD="\$(CXX)"
+  GCJ_FOR_BUILD="\$(GCJ)"
+  GFORTRAN_FOR_BUILD="\$(GFORTRAN)"
+  DLLTOOL_FOR_BUILD="\$(DLLTOOL)"
+  LD_FOR_BUILD="\$(LD)"
+  NM_FOR_BUILD="\$(NM)"
+  RANLIB_FOR_BUILD="\$(RANLIB)"
+  WINDRES_FOR_BUILD="\$(WINDRES)"
+  WINDMC_FOR_BUILD="\$(WINDMC)"
 fi
 
 AC_PROG_CC
@@ -2365,6 +2388,8 @@ esac
 # Allow the user to override the flags for
 # our build compiler if desired.
 CFLAGS_FOR_BUILD=${CFLAGS_FOR_BUILD-${CFLAGS}}
+CXXFLAGS_FOR_BUILD=${CXXFLAGS_FOR_BUILD-${CFLAGS}}
+LDFLAGS_FOR_BUILD=${LDFLAGS_FOR_BUILD-${CFLAGS}}
 
 # On Canadian crosses, we'll be searching the right directories for
 # the previously-installed cross compiler, so don't bother to add
@@ -2422,7 +2447,21 @@ AC_SUBST(target_configargs)
 
 
 # Build tools.
+AC_SUBST(AR_FOR_BUILD)
+AC_SUBST(AS_FOR_BUILD)
 AC_SUBST(CC_FOR_BUILD)
+AC_SUBST(CFLAGS_FOR_BUILD)
+AC_SUBST(CXXFLAGS_FOR_BUILD)
+AC_SUBST(CXX_FOR_BUILD)
+AC_SUBST(DLLTOOL_FOR_BUILD)
+AC_SUBST(GCJ_FOR_BUILD)
+AC_SUBST(GFORTRAN_FOR_BUILD)
+AC_SUBST(LDFLAGS_FOR_BUILD)
+AC_SUBST(LD_FOR_BUILD)
+AC_SUBST(NM_FOR_BUILD)
+AC_SUBST(RANLIB_FOR_BUILD)
+AC_SUBST(WINDMC_FOR_BUILD)
+AC_SUBST(WINDRES_FOR_BUILD)
 AC_SUBST(config_shell)
 
 # Generate default definitions for YACC, M4, LEX and other programs that run
@@ -2507,7 +2546,6 @@ NCN_STRICT_CHECK_TOOLS(OBJDUMP, objdump)
 AC_SUBST(CC)
 AC_SUBST(CXX)
 AC_SUBST(CFLAGS)
-AC_SUBST(CFLAGS_FOR_BUILD)
 AC_SUBST(CXXFLAGS)
 
 # Target tools.