# crossdev --b 2.25-r1 --g 4.9.1 --k 4.0 --l 2.19 --target i686-pc-linux-gnu -P -v
ERROR: Invalid atom: '/'
 * You need to specify an output overlay.  Please use --ov-output, or consult
 * https://wiki.gentoo.org/wiki/Overlay/Local_overlay for more details.

I did the diff's backwards (sorry), the newer version is the -, older is the +

# diff -u -r . /mnt/nfs/borg/usr/share/crossdev
diff -u -r ./include/site/linux /mnt/nfs/borg/usr/share/crossdev/include/site/linux
--- ./include/site/linux	2015-05-25 02:51:12.000000000 -0700
+++ /mnt/nfs/borg/usr/share/crossdev/include/site/linux	2014-07-28 22:50:38.000000000 -0700
@@ -30,8 +30,6 @@
 
 
 ac_cv_file__bin_bash=yes
-ac_cv_file__dev_ptmx=yes
-ac_cv_file__dev_ptc=no
 ac_cv_file__dev_srandom=yes
 ac_cv_file__dev_urandom=yes
 ac_cv_file__dev_random=yes
diff -u -r ./include/site/linux-gnueabi /mnt/nfs/borg/usr/share/crossdev/include/site/linux-gnueabi
--- ./include/site/linux-gnueabi	2015-05-25 02:51:12.000000000 -0700
+++ /mnt/nfs/borg/usr/share/crossdev/include/site/linux-gnueabi	2014-07-28 22:50:38.000000000 -0700
@@ -294,4 +294,8 @@
 
 
 # enca
+ac_cv_file__dev_srandom=yes
+ac_cv_file__dev_urandom=yes
+ac_cv_file__dev_random=yes
+ac_cv_file__dev_arandom=no
 yeti_cv_func_scanf_modif_size_t=z

# diff -u ./cross-emerge /mnt/nfs/borg/usr/bin/cross-emerge
--- ./cross-emerge	2015-05-26 05:21:58.619901807 -0700
+++ /mnt/nfs/borg/usr/bin/cross-emerge	2014-11-01 18:01:36.000000000 -0700
@@ -30,5 +30,10 @@
 : ${BUILD_CPPFLAGS=${_E_CPPFLAGS}}
 export CBUILD BUILD_CFLAGS BUILD_CXXFLAGS BUILD_CPPFLAGS
 
+FAKEROOT=
+if [ $(id -u) -ne 0 ] ; then
+	type -P fakeroot >/dev/null && FAKEROOT=fakeroot
+fi
+
 : ${CROSS_CMD:=emerge --root-deps=rdeps}
-exec ${CROSS_CMD} "$@"
+exec ${FAKEROOT} ${CROSS_CMD} "$[~divinespear]

# diff -u ./cross-fix-root /mnt/nfs/borg/usr/bin/cross-fix-root
# 

# diff -u ./cross-pkg-config /mnt/nfs/borg/usr/bin/cross-pkg-config
--- ./cross-pkg-config	2015-05-26 05:21:58.620901789 -0700
+++ /mnt/nfs/borg/usr/bin/cross-pkg-config	2014-11-01 18:01:36.000000000 -0700
@@ -82,12 +82,12 @@
 #
 : ${ABI:=${DEFAULT_ABI:-default}}
 var="LIBDIR_${ABI}"
-eval libdir=\${${var}}
+libdir=${!var}
 if [ -z "${libdir}" ] ; then
 	# Fall back to probing the compiler.
-	libdir=$(realpath "$(${CC:-${CHOST}-gcc} ${CFLAGS} ${LDFLAGS} -print-file-name=pkgconfig)/..")
+	libc=$(realpath $(${CC:-${CHOST}-gcc} ${CFLAGS} ${LDFLAGS} -print-file-name=libc.so))
 	# Chopping the basename isn't exactly correct, but it's good enough for now.
-	libdir=$(basename "${libdir}")
+	libdir=$(basename "${libc%/*}")
 fi
 : ${libdir:=lib}
 export PKG_CONFIG_SYSTEM_LIBRARY_PATH="/usr/${libdir}:/${libdir}"

# diff -u ./emerge-wrapper /mnt/nfs/borg/usr/bin/emerge-wrapper
--- ./emerge-wrapper	2015-05-26 05:21:58.629901625 -0700
+++ /mnt/nfs/borg/usr/bin/emerge-wrapper	2014-11-01 18:01:36.000000000 -0700
@@ -21,13 +21,11 @@
 
 emit_setup_warning()
 {
-	if ! ${setup_warning} ; then
-		setup_warning=true
-		echo "!!! WARNING - Cannot auto-configure CHOST ${CHOST};"
-		echo "!!! You should edit ${conf}"
-		echo "!!! by hand to complete your configuration."
-	fi
-	echo "!!!  $*"
+	${setup_warning:-false} && return 0
+	setup_warning=true
+	echo "!!! WARNING - Cannot auto-configure CHOST ${CHOST}"
+	echo "!!! You should edit ${conf}"
+	echo "!!! by hand to complete your configuration"
 }
 
 cross_wrap_etc()
@@ -43,17 +41,16 @@
 	# Re-use existing CHOST->portage ARCH mapping code
 	ARCH=$(
 		inherit() { :; }
-		. "${MAIN_REPO_PATH}"/eclass/toolchain-funcs.eclass
+		. "${PORTDIR}"/eclass/toolchain-funcs.eclass
 		tc-arch
 	)
-	[[ ${ARCH} == "unknown" ]] && emit_setup_warning "No ARCH is known for this target."
+	[[ ${ARCH} == "unknown" ]] && emit_setup_warning
 
 	LIBC="__LIBC__"
 	case ${CHOST} in
-	*gnu*)    LIBC=glibc ;;
-	*uclibc*) LIBC=uclibc ;;
-	*mingw*)  LIBC=mingw ;;
-	*)        emit_setup_warning "No LIBC is known for this target." ;;
+		*gnu*)    LIBC=glibc ;;
+		*uclibc*) LIBC=uclibc ;;
+		*)        emit_setup_warning ;;
 	esac
 
 	sed -i \
@@ -112,12 +109,10 @@
 
 # CBUILD must be the first thing we export, but might as well avoid
 # running portageq multiple times ...
-import_vars="DISTDIR MAKEOPTS GENTOO_MIRRORS"
+import_vars="PORTDIR DISTDIR PORTDIR_OVERLAY MAKEOPTS GENTOO_MIRRORS"
 eval $(portageq envvar -v CBUILD ${import_vars})
 export CBUILD
 
-MAIN_REPO_PATH=$(crossdev --show-repo-cfg MAIN_REPO_PATH)
-
 # Get default CHOST value from program name
 CHOST=${0##*/}
 CHOST=${CHOST%-emerge}