diff --git a/etc/README.md b/etc/README.md
index 9cce568..c1be480 100644
--- a/etc/README.md
+++ b/etc/README.md
@@ -804,7 +804,7 @@ VERSION`` and/or ``URLS_GIT``, respectively.
 | FlagLine			| String of {SP,VT}-separated flags, arguments, options, etc. pp. to a command                                                                 |
 | List(<sep>[,<sep|type>..])	| <sep>-separated list, optionally recursively and/or sub-typing, e.g.: ``List(:,=,String)`` and ``"name=value:name2=va lue "``                |
 | PkgName			| Single name of package                                                                                                                       |
-| PkgRelation			| Single, possibly parametrised, package-package relation; see section [3.6](#36-package-package-and-packagegroup-group-relationships)        |
+| PkgRelation			| Single, possibly parametrised, package-package relation; see section [3.6](#36-package-package-and-packagegroup-group-relationships)         |
 | PkgVersion			| Single version of package                                                                                                                    |
 | Set(<type>)			| Set of alternatives of <type>, e.g. one of ``cross``, ``host``, ``native``                                                                   |
 | String			| Semantically generic string                                                                                                                  |
@@ -818,12 +818,13 @@ VERSION`` and/or ``URLS_GIT``, respectively.
 | Package variable name        | Type             | Description                                                                                                                                |
 | ---------------------------- | ---------------- | ------------------------------------------------------------------------------------------------------------------------------------------ |
 | AR                           | CmdName          | Toolchain library archive editor ``ar(1)``                                                                                                 |
+| AUTOCONF_CONFIG_GUESS        | String           | Either of ``midipix`` (copy Midipix ``config.guess`` from ``etc/config.guess``) or ``keep``; defaults to ``midipix``                       |
 | BASE_DIR                     | DirName(Abs)     | Package build root directory beneath ``${BUILD_WORKDIR}``                                                                                  |
 | BUILD_DIR                    | DirName(Unit)    | Package build directory beneath ``${PKG_BASE_DIR}``                                                                                        |
 | BUILD_STAGES_DISABLE         | List( )          | Build stages to disable during package build                                                                                               |
 | BUILD_TYPE                   | Set(String)      | ``cross``: Cross-compiled toolchain, ``host``: host, ``native``: cross-compiled package                                                    |
 | CC                           | FileName         | Toolchain C compiler ``cc(1)``                                                                                                             |
-| CFLAGS_BUILD_EXTRA           | FlagLine         | Additional C compiler flags during package ``make(1)``  build                                                                              |
+| CFLAGS_BUILD_EXTRA           | FlagLine         | Additional C compiler flags during package ``make(1)`` build                                                                               |
 | CFLAGS_BUILD                 | FlagLine         | C compiler flags during package ``make(1)``  build                                                                                         |
 | CFLAGS_CONFIGURE_EXTRA       | FlagLine         | Additional C compiler flags during package (GNU autotools in implementation and/or interface) configuration                                |
 | CFLAGS_CONFIGURE             | FlagLine         | C compiler flags during package (GNU autotools in implementation and/or interface) configuration                                           |
diff --git a/groups/010.host_deps.group b/groups/010.host_deps.group
index d9e44a1..05392d3 100644
--- a/groups/010.host_deps.group
+++ b/groups/010.host_deps.group
@@ -23,8 +23,10 @@ HOST_DEPS_PREFIX="${PREFIX}";
 : ${PKG_BINUTILS_BUILD_SHA256SUM:=250d3b2925c6b211fb16173b0b25bc091c58829fbcad3eb849645e0af52cf7fa};
 : ${PKG_BINUTILS_BUILD_VERSION:=2.24.51};
 : ${PKG_BINUTILS_BUILD_URL:=ftp://sourceware.org/pub/binutils/snapshots/binutils-${PKG_BINUTILS_BUILD_VERSION}.tar.bz2};
+: ${PKG_BINUTILS_BUILD_AUTOCONF_CONFIG_GUESS:="keep"};
 : ${PKG_BINUTILS_BUILD_CONFIGURE_ARGS:="--disable-werror --enable-deterministic-archives --enable-install-libbfd --prefix=${PREFIX}/opt"};
 : ${PKG_BINUTILS_BUILD_LIBTOOL:=slibtool-static};
+: ${PKG_BINUTILS_BUILD_PATCHES_EXTRA:="${BUILD_WORKDIR}/chainport/patches/binutils/binutils-${PKG_BINUTILS_BUILD_VERSION}.midipix.patch"};
 : ${PKG_BINUTILS_BUILD_PREFIX:="${PREFIX}/opt"};
 : ${PKG_BINUTILS_BUILD_VARS_FILE:="vars/binutils.vars"};
 : ${PKG_BISON_HOST_DEPENDS:="readline_host"};
diff --git a/groups/030.host_toolchain.group b/groups/030.host_toolchain.group
index 09bf01d..59ccae7 100644
--- a/groups/030.host_toolchain.group
+++ b/groups/030.host_toolchain.group
@@ -15,6 +15,7 @@ HOST_TOOLCHAIN_PREFIX="${PREFIX_CROSS}";
 : ${PKG_BINUTILS_HOST_SHA256SUM:=250d3b2925c6b211fb16173b0b25bc091c58829fbcad3eb849645e0af52cf7fa};
 : ${PKG_BINUTILS_HOST_VERSION:=2.24.51};
 : ${PKG_BINUTILS_HOST_URL:=ftp://sourceware.org/pub/binutils/snapshots/binutils-${PKG_BINUTILS_HOST_VERSION}.tar.bz2};
+: ${PKG_BINUTILS_HOST_AUTOCONF_CONFIG_GUESS:="keep"};
 : ${PKG_BINUTILS_HOST_CFLAGS_CONFIGURE:="-I${PREFIX}/include -g2 -O0"};
 : ${PKG_BINUTILS_HOST_CONFIGURE_ARGS:="--disable-werror --enable-deterministic-archives --prefix=${PREFIX} --target=${DEFAULT_TARGET} --with-sysroot=${PREFIX_CROSS}"};
 : ${PKG_BINUTILS_HOST_INSTALL_FILES_V2:="
@@ -29,6 +30,7 @@ HOST_TOOLCHAIN_PREFIX="${PREFIX_CROSS}";
 : ${PKG_BINUTILS_HOST_MINGW32_SHA256SUM:=250d3b2925c6b211fb16173b0b25bc091c58829fbcad3eb849645e0af52cf7fa};
 : ${PKG_BINUTILS_HOST_MINGW32_VERSION:=2.24.51};
 : ${PKG_BINUTILS_HOST_MINGW32_URL:=ftp://sourceware.org/pub/binutils/snapshots/binutils-${PKG_BINUTILS_HOST_MINGW32_VERSION}.tar.bz2};
+: ${PKG_BINUTILS_HOST_MINGW32_AUTOCONF_CONFIG_GUESS:="keep"};
 : ${PKG_BINUTILS_HOST_MINGW32_CONFIGURE_ARGS:="--disable-nls --disable-werror --enable-deterministic-archives --prefix=${PREFIX} --target=x86_64-w64-mingw32 --with-sysroot=${PREFIX_MINGW32}"};
 : ${PKG_BINUTILS_HOST_MINGW32_LIBTOOL:=slibtool-static};
 : ${PKG_BINUTILS_HOST_MINGW32_MAKEFLAGS_INSTALL:="PREFIX= prefix="};
diff --git a/groups/110.native_toolchain.group b/groups/110.native_toolchain.group
index 6bac875..9fcbe96 100644
--- a/groups/110.native_toolchain.group
+++ b/groups/110.native_toolchain.group
@@ -9,6 +9,7 @@ NATIVE_TOOLCHAIN_PREFIX="${PREFIX_NATIVE}";
 : ${PKG_BINUTILS_SHA256SUM:=250d3b2925c6b211fb16173b0b25bc091c58829fbcad3eb849645e0af52cf7fa};
 : ${PKG_BINUTILS_VERSION:=2.24.51};
 : ${PKG_BINUTILS_URL:=ftp://sourceware.org/pub/binutils/snapshots/binutils-${PKG_BINUTILS_VERSION}.tar.bz2};
+: ${PKG_BINUTILS_AUTOCONF_CONFIG_GUESS:="keep"};
 : ${PKG_BINUTILS_CONFIGURE_ARGS_EXTRA:="--enable-deterministic-archives --with-libelf=${PREFIX_NATIVE} --with-gmp=${PREFIX_NATIVE} --with-mpc=${PREFIX_NATIVE} --with-mpfr=${PREFIX_NATIVE} --with-sysroot=/"};
 : ${PKG_BINUTILS_CFLAGS_CONFIGURE:="-isystem ${PREFIX_NATIVE}/include -Wno-error=cpp"};
 : ${PKG_BINUTILS_LDFLAGS_CONFIGURE:="-L${PREFIX_NATIVE}/lib"};
@@ -22,6 +23,7 @@ NATIVE_TOOLCHAIN_PREFIX="${PREFIX_NATIVE}";
 : ${PKG_BINUTILS_MINGW32_SHA256SUM:=250d3b2925c6b211fb16173b0b25bc091c58829fbcad3eb849645e0af52cf7fa};
 : ${PKG_BINUTILS_MINGW32_VERSION:=2.24.51};
 : ${PKG_BINUTILS_MINGW32_URL:=ftp://sourceware.org/pub/binutils/snapshots/binutils-${PKG_BINUTILS_MINGW32_VERSION}.tar.bz2};
+: ${PKG_BINUTILS_MINGW32_AUTOCONF_CONFIG_GUESS:="keep"};
 : ${PKG_BINUTILS_MINGW32_CONFIGURE_ARGS:="--disable-nls --enable-deterministic-archives --host=${DEFAULT_TARGET} --prefix=/ --target=x86_64-w64-mingw32 --with-libelf=${PREFIX_NATIVE} --with-gmp=${PREFIX_NATIVE} --with-mpc=${PREFIX_NATIVE} --with-mpfr=${PREFIX_NATIVE} --with-sysroot=/"};
 : ${PKG_BINUTILS_MINGW32_PATCHES_EXTRA:="${BUILD_WORKDIR}/chainport/patches/binutils/binutils-${PKG_BINUTILS_MINGW32_VERSION}.midipix.patch"};
 : ${PKG_BINUTILS_MINGW32_PREFIX:="${PREFIX_NATIVE}"};
diff --git a/midipix.env b/midipix.env
index 501eb14..b9e83fb 100644
--- a/midipix.env
+++ b/midipix.env
@@ -18,24 +18,24 @@ DEFAULT_BUILD_STEPS="											\
 	clean												\
 	finish";
 DEFAULT_BUILD_VARS="											\
-	AR BASE_DIR BUILD_DIR BUILD_STEPS_DISABLE BUILD_TYPE CC CFLAGS_BUILD				\
-	CFLAGS_BUILD_EXTRA CFLAGS_CONFIGURE CFLAGS_CONFIGURE_EXTRA CMAKE				\
-	CMAKE_ARGS CMAKE_ARGS_EXTRA CMAKE_LISTFILE CONFIG_CACHE CONFIG_CACHE_EXTRA			\
-	CONFIG_CACHE_LOCAL CONFIGURE CONFIGURE_ARGS CONFIGURE_ARGS_EXTRA				\
-	CONFIGURE_TYPE CXX CXXFLAGS_CONFIGURE CXXFLAGS_CONFIGURE_EXTRA DEPENDS				\
-	DESTDIR DESTDIR_HOST DISABLED ENV_VARS_EXTRA FNAME FORCE_AUTORECONF				\
-	GITROOT INHERIT_FROM INSTALL_FILES INSTALL_FILES_DESTDIR					\
-	INSTALL_FILES_DESTDIR_EXTRA INSTALL_FILES_V2 INSTALL_TARGET INSTALL_TARGET_EXTRA		\
-	IN_TREE LDFLAGS_BUILD_EXTRA LDFLAGS_CONFIGURE LDFLAGS_CONFIGURE_EXTRA				\
-	LIBTOOL MAKE MAKEFLAGS_BUILD MAKEFLAGS_BUILD_EXTRA MAKEFLAGS_INSTALL				\
-	MAKEFLAGS_INSTALL_EXTRA MAKEFLAGS_VERBOSITY MAKE_INSTALL_VNAME					\
-	MAKE_SUBDIRS MIRRORS MIRRORS_GIT NO_CLEAN NO_CLEAN_BASE_DIR NO_LOG_VARS				\
-	PATCHES_EXTRA PKG_CONFIG PKG_CONFIG_LIBDIR PKGLIST_DISABLE PREFIX				\
-	PYTHON RANLIB RPM_DISABLE SHA256SUM SOFORT_NATIVE_CC						\
-	SOFORT_NATIVE_CFLAGS SOFORT_NATIVE_CFLAGS_EXTRA SOFORT_NATIVE_CXX				\
-	SOFORT_NATIVE_CXXFLAGS SOFORT_NATIVE_CXXFLAGS_EXTRA SOFORT_NATIVE_LD				\
-	SOFORT_NATIVE_LDFLAGS SOFORT_NATIVE_LDFLAGS_EXTRA SUBDIR TARGET URL				\
-	URLS_GIT VARS_FILE VERSION";
+	AR AUTOCONF_CONFIG_GUESS BASE_DIR BUILD_DIR BUILD_STEPS_DISABLE BUILD_TYPE			\
+	CC CFLAGS_BUILD CFLAGS_BUILD_EXTRA CFLAGS_CONFIGURE CFLAGS_CONFIGURE_EXTRA			\
+	CMAKE CMAKE_ARGS CMAKE_ARGS_EXTRA CMAKE_LISTFILE CONFIG_CACHE					\
+	CONFIG_CACHE_EXTRA CONFIG_CACHE_LOCAL CONFIGURE CONFIGURE_ARGS					\
+	CONFIGURE_ARGS_EXTRA CONFIGURE_TYPE CXX CXXFLAGS_CONFIGURE					\
+	CXXFLAGS_CONFIGURE_EXTRA DEPENDS DESTDIR DESTDIR_HOST DISABLED					\
+	ENV_VARS_EXTRA FNAME FORCE_AUTORECONF GITROOT INHERIT_FROM INSTALL_FILES			\
+	INSTALL_FILES_DESTDIR INSTALL_FILES_DESTDIR_EXTRA INSTALL_FILES_V2				\
+	INSTALL_TARGET INSTALL_TARGET_EXTRA IN_TREE LDFLAGS_BUILD_EXTRA					\
+	LDFLAGS_CONFIGURE LDFLAGS_CONFIGURE_EXTRA LIBTOOL MAKE MAKEFLAGS_BUILD				\
+	MAKEFLAGS_BUILD_EXTRA MAKEFLAGS_INSTALL MAKEFLAGS_INSTALL_EXTRA					\
+	MAKEFLAGS_VERBOSITY MAKE_INSTALL_VNAME MAKE_SUBDIRS MIRRORS MIRRORS_GIT				\
+	NO_CLEAN NO_CLEAN_BASE_DIR NO_LOG_VARS PATCHES_EXTRA PKG_CONFIG					\
+	PKG_CONFIG_LIBDIR PKGLIST_DISABLE PREFIX PYTHON RANLIB RPM_DISABLE				\
+	SHA256SUM SOFORT_NATIVE_CC SOFORT_NATIVE_CFLAGS SOFORT_NATIVE_CFLAGS_EXTRA			\
+	SOFORT_NATIVE_CXX SOFORT_NATIVE_CXXFLAGS SOFORT_NATIVE_CXXFLAGS_EXTRA				\
+	SOFORT_NATIVE_LD SOFORT_NATIVE_LDFLAGS SOFORT_NATIVE_LDFLAGS_EXTRA SUBDIR			\
+	TARGET URL URLS_GIT VARS_FILE VERSION";
 
 #
 # Prerequisite commands
@@ -165,6 +165,7 @@ https://midipix.lucioillanes.de/repos_git/								\
 
 #
 # Default command & tool flags & variables
+: ${DEFAULT_AUTOCONF_CONFIG_GUESS:="midipix"};
 : ${DEFAULT_CMAKE_LISTFILE:="CMakeLists.txt"};
 : ${DEFAULT_GITROOT:=git://midipix.org};
 : ${DEFAULT_GITROOT_HEAD:=git://midipix.org};
diff --git a/patches/binutils_build-2.24.51.local.patch b/patches/binutils_build-2.24.51.local.patch
new file mode 120000
index 0000000..7e0db75
--- /dev/null
+++ b/patches/binutils_build-2.24.51.local.patch
@@ -0,0 +1 @@
+binutils-2.24.51.local.patch
\ No newline at end of file
diff --git a/subr/pkg_configure_autotools.subr b/subr/pkg_configure_autotools.subr
index 4f7f76e..15d7656 100644
--- a/subr/pkg_configure_autotools.subr
+++ b/subr/pkg_configure_autotools.subr
@@ -3,15 +3,22 @@
 #
 
 pkg_configure_autotools() {
-	local _config_cache="" _fname="" _subdir_tgt="";
+	local _config_cache="" _config_guest_fname="" _fname="" _subdir_tgt="";
 
 	if [ "${PKG_CONFIGURE_TYPE:+1}" = 1 ]\
 	&& [ "${PKG_CONFIGURE_TYPE}" != "autotools" ]; then
 		return 0;
 	fi;
 
+	if [ "${PKG_AUTOCONF_CONFIG_GUESS:-midipix}" = "midipix" ]; then
+		_config_guest_fname="config.guess";
+	else
+		_config_guest_fname="";
+	fi;
+
 	if rtl_exists_any "${PKG_BASE_DIR}/${PKG_SUBDIR}"							\
-			"config.guess" "configure.ac" "configure.in" "configure";
+			${_config_guest_fname:+"${_config_guest_fname}"}					\
+			"configure.ac" "configure.in" "configure";
 	then	rtl_export_vars PKG_CONFIG "${PKG_PKG_CONFIG:-}" PKG_CONFIG_LIBDIR "${PKG_PKG_CONFIG_LIBDIR:-}";
 		if [ "${PKG_FORCE_AUTORECONF:-0}" -eq 1 ]\
 		&& ! (cd "${PKG_BASE_DIR}/${PKG_SUBDIR}" && autoreconf -fiv); then
@@ -29,12 +36,15 @@ pkg_configure_autotools() {
 									"${MIDIPIX_BUILD_PWD}/etc/config.sub"	\
 									"${_subdir_tgt}/config.sub"; then
 								return 1;
-							elif ! rtl_fileop install -m 0700			\
-									"${MIDIPIX_BUILD_PWD}/etc/config.guess"	\
-									"${_subdir_tgt}/config.guess"; then
-								return 1;
-							else
-								break;
+							fi;
+							if [ "${PKG_AUTOCONF_CONFIG_GUESS:-midipix}" = "midipix" ]; then
+								if ! rtl_fileop install -m 0700			\
+										"${MIDIPIX_BUILD_PWD}/etc/config.guess"\
+										"${_subdir_tgt}/config.guess"; then
+									return 1;
+								else
+									break;
+								fi;
 							fi;
 						fi;
 					done;
@@ -55,13 +65,15 @@ pkg_configure_autotools() {
 			|| ! rtl_fileop install -m 0700 "${MIDIPIX_BUILD_PWD}/etc/config.sub" "${_fname}"; then
 				return 1;
 			fi;
-		done
-		for _fname in $(find "${PKG_BASE_DIR}/${PKG_SUBDIR}" -name config.guess); do
-			if ! rtl_fileop mv "${_fname}" "${_fname}.orig"\
-			|| ! rtl_fileop install -m 0700 "${MIDIPIX_BUILD_PWD}/etc/config.guess" "${_fname}"; then
-				return 1;
-			fi;
-		done
+		done;
+		if [ "${PKG_AUTOCONF_CONFIG_GUESS:-midipix}" = "midipix" ]; then
+			for _fname in $(find "${PKG_BASE_DIR}/${PKG_SUBDIR}" -name config.guess); do
+				if ! rtl_fileop mv "${_fname}" "${_fname}.orig"\
+				|| ! rtl_fileop install -m 0700 "${MIDIPIX_BUILD_PWD}/etc/config.guess" "${_fname}"; then
+					return 1;
+				fi;
+			done;
+		fi;
 		if [ "${PKG_BUILD_TYPE}" != host ]; then
 			if ! rtl_fileop touch "${PKG_BUILD_DIR}/config.cache"; then
 				return 1;