Index: /trunk/tools/linux.x86/kmodbuild/build-kernel.sh
===================================================================
--- /trunk/tools/linux.x86/kmodbuild/build-kernel.sh	(revision 78140)
+++ /trunk/tools/linux.x86/kmodbuild/build-kernel.sh	(revision 78140)
@@ -0,0 +1,522 @@
+#!/bin/bash
+# $Id$
+## @file
+# Script for build a linux kernel with a default configuration.
+#
+# This script assumes gcc-6, gcc-4.9 and gcc-3.3 are available on the system.
+#
+# For really old kernels make 3.80 and 3.76 will need to be built and put in
+# a specific place relative to the kernel sources.
+#
+# This script may patch the kernel source a little to work around issues with
+# newere binutils, perl, glibc and maybe compilers.
+#
+# It is recommended to use a overlayfs setup and kDeDup the kernel sources to
+# save disk space.
+#
+
+#
+# Copyright (C) 2019 Oracle Corporation
+#
+# This file is part of VirtualBox Open Source Edition (OSE), as
+# available from http://www.virtualbox.org. This file is free software;
+# you can redistribute it and/or modify it under the terms of the GNU
+# General Public License (GPL) as published by the Free Software
+# Foundation, in version 2 as it comes in the "COPYING" file of the
+# VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+# hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+#
+
+if [ -z "${JOBS}" ]; then JOBS=42; fi
+
+#
+# The path argument.
+#
+if [ "$#" -lt "1" ]; then
+    echo "usage: build.sh <dir> [clean]"
+    exit 2
+fi
+
+set -e
+echo "********************************************************************************"
+echo "*   $1"
+echo "********************************************************************************"
+set -x
+shopt -s extglob
+
+# Enter it.
+cd "$1"
+
+# Change the terminal title (ASSUMES xterm-like TERM).
+KERN_SUBDIR=`basename $1`
+export PS1="\$ ";
+echo -ne "\033]0;build.sh - ${KERN_SUBDIR}\007"
+
+# Derive the version from it.
+KERN_VER=`echo $1 | sed -e 's/^.*linux-\([0-9][0-9.]*\).*$/\1/'`
+case "${KERN_VER}" in
+    [0-9].[0-9]|[0-9].[0-9][0-9]|[0-9][0-9].[0-9]|[0-9][0-9].[0-9][0-9])
+        KERN_VER_3PLUS_DOTS="${KERN_VER}.0";;
+    *)
+        KERN_VER_3PLUS_DOTS=${KERN_VER};;
+esac
+echo "debug: KERN_VER=${KERN_VER}  --> KERN_VER_3PLUS_DOTS=${KERN_VER_3PLUS_DOTS}"
+
+# Determin tool overrides.
+OVERRIDES=
+MAKE=/usr/bin/make
+case "${KERN_VER_3PLUS_DOTS}" in
+    4.9.*|4.1[0-7].*)
+        OVERRIDES="CC=gcc-6 CXX=g++-6"
+        ;;
+    2.6.3[789]*|3.*|4.[0-8].*)
+        OVERRIDES="CC=gcc-4.9 CXX=g++-4.9"
+        ;;
+    2.6.29*|2.6.3[0-9]*)
+        OVERRIDES="CC=gcc-3.3 CXX=g++-3.3"
+        ;;
+    2.6.[89]*|2.6.12[0-9]*|2.6.2[0-8]*)
+        OVERRIDES="CC=gcc-3.3 CXX=g++-3.3"
+        MAKE=../../make-3.80/installed/bin/make
+        ;;
+    2.6.*)
+        OVERRIDES="CC=gcc-3.3 CXX=g++-3.3"
+        MAKE=../../make-3.80/installed/bin/make
+        ;;
+esac
+echo "debug: OVERRIDES=${OVERRIDES}  MAKE=${MAKE}"
+
+echo "${OVERRIDES}" > .bird-overrides
+ln -sf "${MAKE}" .bird-make
+
+# Done with arg #1.
+shift
+
+
+#
+# Apply patches for newer tools and stuff.
+#
+
+# perl --annoying
+if [ -f kernel/timeconst.pl ]; then
+    if patch --output /tmp/build.$$ -Np1 <<EOF
+--- a/kernel/timeconst.pl	2019-04-15 13:44:55.434946090 +0200
++++ b/kernel/timeconst.pl	2019-04-15 13:57:29.330140587 +0200
+@@ -372,5 +372,5 @@
+ 	@val = @{\$canned_values{\$hz}};
+-	if (!defined(@val)) {
++	if (!@val) {
+ 		@val = compute_values(\$hz);
+ 	}
+ 	output(\$hz, @val);
+EOF
+    then
+        cp /tmp/build.$$ kernel/timeconst.pl
+    fi
+fi
+
+# binutils PLT32
+case "${KERN_VER_3PLUS_DOTS}" in
+    4.10.*|4.11.*|4.12.*|4.13.*|4.14.*|4.15.*|4.16.*)
+        if patch --output /tmp/build.$$ -Np1 <<EOF
+diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
+index 1f790cf9d38f..3b7427aa7d85 100644
+--- a/arch/x86/kernel/machine_kexec_64.c
++++ b/arch/x86/kernel/machine_kexec_64.c
+@@ -542,6 +542,7 @@ int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,
+ 				goto overflow;
+ 			break;
+ 		case R_X86_64_PC32:
++		case R_X86_64_PLT32:
+ 			value -= (u64)address;
+ 			*(u32 *)location = value;
+ 			break;
+EOF
+then
+            cp /tmp/build.$$ arch/x86/kernel/machine_kexec_64.c
+        fi
+        case "${KERN_VER}" in
+            4.10.*|4.11.*|4.12.*|4.13.*)
+                if patch --output /tmp/build.$$ -Np1 <<EOF
+diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
+index da0c160e5589..f58336af095c 100644
+--- a/arch/x86/kernel/module.c
++++ b/arch/x86/kernel/module.c
+@@ -191,6 +191,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
+ 				goto overflow;
+ 			break;
+ 		case R_X86_64_PC32:
++		case R_X86_64_PLT32:
+ 			val -= (u64)loc;
+ 			*(u32 *)loc = val;
+ #if 0
+EOF
+                then
+                    cp /tmp/build.$$ arch/x86/kernel/module.c
+                fi;;
+            **)
+                if patch --output /tmp/build.$$ -Np1 <<EOF
+diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
+index da0c160e5589..f58336af095c 100644
+--- a/arch/x86/kernel/module.c
++++ b/arch/x86/kernel/module.c
+@@ -191,6 +191,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
+ 				goto overflow;
+ 			break;
+ 		case R_X86_64_PC32:
++		case R_X86_64_PLT32:
+ 			if (*(u32 *)loc != 0)
+ 				goto invalid_relocation;
+ 			val -= (u64)loc;
+EOF
+                then
+                    cp /tmp/build.$$ arch/x86/kernel/module.c
+                fi;;
+        esac
+        if patch --output /tmp/build.$$ -Np1 <<EOF
+diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
+index 5d73c443e778..220e97841e49 100644
+--- a/arch/x86/tools/relocs.c
++++ b/arch/x86/tools/relocs.c
+@@ -770,9 +770,12 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
+ 		break;
+
+ 	case R_X86_64_PC32:
++	case R_X86_64_PLT32:
+ 		/*
+ 		 * PC relative relocations don't need to be adjusted unless
+ 		 * referencing a percpu symbol.
++		 *
++		 * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
+ 		 */
+ 		if (is_percpu_sym(sym, symname))
+ 			add_reloc(&relocs32neg, offset);
+EOF
+        then
+            cp /tmp/build.$$ arch/x86/tools/relocs.c
+        fi
+        if patch --output /tmp/build.$$ -Np1 <<EOF
+--- linux-4.15/tools/lib/subcmd/pager.c	2017-11-12 19:46:13.000000000 +0100
++++ linux-4.17/tools/lib/subcmd/pager.c	2018-06-03 23:15:21.000000000 +0200
+@@ -30,10 +30,13 @@
+ 	 * have real input
+ 	 */
+ 	fd_set in;
++	fd_set exception;
+
+ 	FD_ZERO(&in);
++	FD_ZERO(&exception);
+ 	FD_SET(0, &in);
+-	select(1, &in, NULL, &in, NULL);
++	FD_SET(0, &exception);
++	select(1, &in, NULL, &exception, NULL);
+
+ 	setenv("LESS", "FRSX", 0);
+ }
+EOF
+        then
+            cp /tmp/build.$$ tools/lib/subcmd/pager.c
+        fi
+        if patch --output /tmp/build.$$ -Np1 <<EOF
+--- linux-4.16/tools/lib/str_error_r.c	2019-04-15 06:04:50.978464217 +0200
++++ linux-4.17/tools/lib/str_error_r.c	2018-06-03 23:15:21.000000000 +0200
+@@ -22,6 +22,6 @@
+ {
+ 	int err = strerror_r(errnum, buf, buflen);
+ 	if (err)
+-		snprintf(buf, buflen, "INTERNAL ERROR: strerror_r(%d, %p, %zd)=%d", errnum, buf, buflen, err);
++		snprintf(buf, buflen, "INTERNAL ERROR: strerror_r(%d, [buf], %zd)=%d", errnum, buflen, err);
+ 	return buf;
+ }
+EOF
+        then
+            cp /tmp/build.$$ tools/lib/str_error_r.c
+        fi
+        ;;
+esac
+
+# Undefined ____ilog2_NaN symbol:
+if [ -f include/linux/log2.h ]; then
+    case "${KERN_VER_3PLUS_DOTS}" in
+        4.10.*|4.[9].*)
+        if patch --output /tmp/build.$$ -Np1 <<EOF
+--- linux-4.10/include/linux/log2.h	2017-02-19 23:34:00.000000000 +0100
++++ linux-4.11/include/linux/log2.h	2017-11-12 19:46:13.000000000 +0100
+@@ -15,14 +15,8 @@
+ #include <linux/types.h>
+ #include <linux/bitops.h>
+
+ /*
+- * deal with unrepresentable constant logarithms
+- */
+-extern __attribute__((const, noreturn))
+-int ____ilog2_NaN(void);
+-
+-/*
+  * non-constant log of base 2 calculators
+  * - the arch may override these in asm/bitops.h if they can be implemented
+  *   more efficiently than using fls() and fls64()
+  * - the arch is not required to handle n==0 if implementing the fallback
+@@ -84,9 +78,9 @@
+  */
+ #define ilog2(n)				\\
+ (						\\
+ 	__builtin_constant_p(n) ? (		\\
+-		(n) < 1 ? ____ilog2_NaN() :	\\
++		(n) < 2 ? 0 :			\\
+ 		(n) & (1ULL << 63) ? 63 :	\\
+ 		(n) & (1ULL << 62) ? 62 :	\\
+ 		(n) & (1ULL << 61) ? 61 :	\\
+ 		(n) & (1ULL << 60) ? 60 :	\\
+@@ -147,12 +141,9 @@
+ 		(n) & (1ULL <<  5) ?  5 :	\\
+ 		(n) & (1ULL <<  4) ?  4 :	\\
+ 		(n) & (1ULL <<  3) ?  3 :	\\
+ 		(n) & (1ULL <<  2) ?  2 :	\\
+-		(n) & (1ULL <<  1) ?  1 :	\\
+-		(n) & (1ULL <<  0) ?  0 :	\\
+-		____ilog2_NaN()			\\
+-				   ) :		\\
++		1 ) :				\\
+ 	(sizeof(n) <= 4) ?			\\
+ 	__ilog2_u32(n) :			\\
+ 	__ilog2_u64(n)				\\
+  )
+EOF
+        then
+            cp /tmp/build.$$ include/linux/log2.h
+        fi
+        ;;
+    esac
+fi
+
+# extern then static current_menu.
+if [ -f scripts/kconfig/lkc.h  -a  -f scripts/kconfig/mconf.c ]; then
+    case "${KERN_VER_3PLUS_DOTS}" in
+        2.6.1[0-9]*|2.6.2[0-9]*|2.6.3[0-9]*|2.6.4[0-9]*)
+            ;;
+        2.5.*|2.6.[012345678])
+            if patch --output /tmp/build.$$ -Np1 <<EOF
+--- linux-2.6.8/scripts/kconfig/mconf.c	2004-08-14 07:36:32.000000000 +0200
++++ linux-2.6.8/scripts/kconfig/mconf.c	2019-04-15 15:52:42.143587966 +0200
+@@ -88,5 +88,5 @@
+ static struct termios ios_org;
+ static int rows = 0, cols = 0;
+-static struct menu *current_menu;
++struct menu *current_menu;
+ static int child_count;
+ static int do_resize;
+EOF
+            then
+                cp /tmp/build.$$ scripts/kconfig/mconf.c
+            fi
+            ;;
+    esac
+fi
+
+# Incorrect END label in arch/x86/lib/copy_user_64.S
+case "${KERN_VER_3PLUS_DOTS}" in
+    2.6.2[456]*)
+        if patch --output /tmp/build.$$ -Np1 <<EOF
+--- linux-2.6.26/arch/x86/lib/copy_user_64.S	2019-04-15 16:21:49.475846822 +0200
++++ linux-2.6.26/arch/x86/lib/copy_user_64.S	2019-04-15 16:21:50.883863141 +0200
+@@ -341,7 +341,7 @@
+ 11:	pop %rax
+ 7:	ret
+ 	CFI_ENDPROC
+-END(copy_user_generic_c)
++END(copy_user_generic_string)
+
+ 	.section __ex_table,"a"
+ 	.quad 1b,3b
+EOF
+        then
+            cp /tmp/build.$$ arch/x86/lib/copy_user_64.S
+        fi
+        ;;
+    2.6.2[0123]*|2.6.19*)
+        if patch --output /tmp/build.$$ -Np1 <<EOF
+--- linux-2.6.23/arch/x86_64/lib/copy_user.S	2019-04-15 16:42:16.898006203 +0200
++++ linux-2.6.23/arch/x86_64/lib/copy_user.S	2019-04-15 16:42:25.906109885 +0200
+@@ -344,7 +344,7 @@
+ 11:	pop %rax
+ 7:	ret
+ 	CFI_ENDPROC
+-END(copy_user_generic_c)
++END(copy_user_generic_string)
+
+ 	.section __ex_table,"a"
+ 	.quad 1b,3b
+EOF
+        then
+            cp /tmp/build.$$ arch/x86_64/lib/copy_user.S
+        fi
+        ;;
+esac
+
+# Increase vdso text segment limit as newer tools/whatever causes it to be too large.
+if [ -f arch/x86_64/vdso/vdso.lds.S ]; then
+    if patch --output /tmp/build.$$ -Np1 <<EOF
+--- linux-2.6.23/arch/x86_64/vdso/vdso.lds.S	2019-04-15 17:20:27.567440594 +0200
++++ linux-2.6.23/arch/x86_64/vdso/vdso.lds.S	2019-04-15 17:20:29.635463886 +0200
+@@ -28,5 +28,5 @@
+   .text           : { *(.text) }		:text
+   .text.ptr       : { *(.text.ptr) }		:text
+-  . = VDSO_PRELINK + 0x900;
++  . = VDSO_PRELINK + 0xa00;
+   .data           : { *(.data) }		:text
+   .bss            : { *(.bss) }			:text
+EOF
+    then
+        cp /tmp/build.$$ arch/x86_64/vdso/vdso.lds.S
+    fi
+fi
+
+# glibc PATH_MAX cleanup affect 2.6.21 and earlier:
+if [ -f scripts/mod/sumversion.c ]; then
+    case "${KERN_VER_3PLUS_DOTS}" in
+        2.6.[0-9]!([0-9])*|2.6.1[0-9]*|2.6.2[01]*)
+            if patch --output /tmp/build.$$ -Np1 <<EOF
+--- linux-2.6.21/scripts/mod/sumversion.c	2007-02-04 19:44:54.000000000 +0100
++++ linux-2.6.21/scripts/mod/sumversion.c	2019-02-15 16:10:12.956678862 +0100
+@@ -7,4 +7,5 @@
+ #include <ctype.h>
+ #include <errno.h>
+ #include <string.h>
++#include <linux/limits.h>
+ #include "modpost.h"
+EOF
+        then
+            cp /tmp/build.$$ scripts/mod/sumversion.c
+        fi
+    esac
+fi
+
+# Problem with "System too big" messages in 2.6.17 and earlier:
+if [ -f arch/x86_64/boot/tools/build.c ]; then
+    case "${KERN_VER_3PLUS_DOTS}" in
+        2.6.[0-9]!([0-9])*|2.6.1[0-7]*)
+            if patch --output /tmp/build.$$ -Np1 <<EOF
+--- linux-2.6.17/arch/x86_64/boot/tools/build.c	2006-01-03 04:21:10.000000000 +0100
++++ linux-2.6.18/arch/x86_64/boot/tools/build.c	2007-02-04 19:44:54.000000000 +0100
+@@ -149,9 +149,7 @@
+ 	sz = sb.st_size;
+ 	fprintf (stderr, "System is %d kB\n", sz/1024);
+ 	sys_size = (sz + 15) / 16;
+-	/* 0x40000*16 = 4.0 MB, reasonable estimate for the current maximum */
+-	if (sys_size > (is_big_kernel ? 0x40000 : DEF_SYSSIZE))
+-		die("System is too big. Try using %smodules.",
+-			is_big_kernel ? "" : "bzImage or ");
++	if (!is_big_kernel && sys_size > DEF_SYSSIZE)
++		die("System is too big. Try using bzImage or modules.");
+ 	while (sz > 0) {
+ 		int l, n;
+EOF
+        then
+            cp /tmp/build.$$ arch/x86_64/boot/tools/build.c
+        fi
+    esac
+fi
+
+# Problem with incorrect mov sizes for segments in 2.6.11 and earlier:
+if [ -f arch/x86_64/kernel/process.c ]; then
+    case "${KERN_VER_3PLUS_DOTS}" in
+        2.6.[0-9]!([0-9])*|2.6.1[01]*)
+            if patch --output /tmp/build.$$ -lNp1 <<EOF
+--- linux-2.6.11/arch/x86_64/kernel/process.c	2005-03-02 08:38:10.000000000 +0100
++++ linux-2.6.11/arch/x86_64/kernel/process.c	2019-02-15 16:57:47.653585327 +0100
+@@ -390,10 +390,10 @@
+ 	p->thread.fs = me->thread.fs;
+ 	p->thread.gs = me->thread.gs;
+
+-	asm("movl %%gs,%0" : "=m" (p->thread.gsindex));
+-	asm("movl %%fs,%0" : "=m" (p->thread.fsindex));
+-	asm("movl %%es,%0" : "=m" (p->thread.es));
+-	asm("movl %%ds,%0" : "=m" (p->thread.ds));
++	asm("movw %%gs,%0" : "=m" (p->thread.gsindex));
++	asm("movw %%fs,%0" : "=m" (p->thread.fsindex));
++	asm("movw %%es,%0" : "=m" (p->thread.es));
++	asm("movw %%ds,%0" : "=m" (p->thread.ds));
+
+ 	if (unlikely(me->thread.io_bitmap_ptr != NULL)) {
+ 		p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
+@@ -456,11 +456,11 @@
+ 	 * Switch DS and ES.
+ 	 * This won't pick up thread selector changes, but I guess that is ok.
+ 	 */
+-	asm volatile("movl %%es,%0" : "=m" (prev->es));
++	asm volatile("movw %%es,%0" : "=m" (prev->es));
+ 	if (unlikely(next->es | prev->es))
+ 		loadsegment(es, next->es);
+
+-	asm volatile ("movl %%ds,%0" : "=m" (prev->ds));
++	asm volatile ("movw %%ds,%0" : "=m" (prev->ds));
+ 	if (unlikely(next->ds | prev->ds))
+ 		loadsegment(ds, next->ds);
+EOF
+        then
+            cp /tmp/build.$$ arch/x86_64/kernel/process.c
+        fi
+    esac
+fi
+
+
+#
+# Other arguments.
+#
+while [ "$#" -gt 0 ];
+do
+    case "$1" in
+        clean)
+            time ./.bird-make ${OVERRIDES} -j ${JOBS} clean
+            ;;
+
+        *)
+            echo "syntax error: $1" 1>&2
+            ;;
+    esac
+    shift
+done
+
+#
+# Configure.
+#
+if [ -f .config ]; then
+    mv -f .config .bird-previous-config
+fi
+nice ./.bird-make ${OVERRIDES} -j ${JOBS} defconfig
+case "${KERN_VER_3PLUS_DOTS}" in
+    2.[012345].*|2.6.[0-9]!([0-9])*|2.6.[12][0-9]*)
+        ;;
+    *)
+        echo CONFIG_DRM_TTM=m >> .config;
+        echo CONFIG_DRM_RADEON=m >> .config
+        echo CONFIG_DRM_RADEON_UMS=y >> .config
+        echo CONFIG_DRM_RADEON_USERPTR=y >> .config
+        echo CONFIG_DRM_RADEON_KMS=y >> .config
+        ;;
+esac
+case "${KERN_VER_3PLUS_DOTS}" in
+    2.4.*)  ;;
+    4.2[0-9].*|4.1[789].*|[5-9].*)
+        nice ./.bird-make ${OVERRIDES} syncconfig;;
+    *)  nice ./.bird-make ${OVERRIDES} silentoldconfig;;
+esac
+if [ -f .bird-previous-config ]; then
+    if cmp -s .config .bird-previous-config; then
+        mv -f .bird-previous-config .config
+    fi
+fi
+
+#
+# Build all.
+#
+if time nice ./.bird-make ${OVERRIDES} -j ${JOBS} all -k; then
+    rm -f .bird-failed
+    echo -ne "\033]0;build.sh - ${KERN_SUBDIR} - done\007"
+else
+    touch .bird-failed
+    echo -ne "\033]0;build.sh - ${KERN_SUBDIR} - failed\007"
+    exit 1
+fi
+
Index: /trunk/tools/linux.x86/kmodbuild/build-modules.sh
===================================================================
--- /trunk/tools/linux.x86/kmodbuild/build-modules.sh	(revision 78140)
+++ /trunk/tools/linux.x86/kmodbuild/build-modules.sh	(revision 78140)
@@ -0,0 +1,87 @@
+#!/bin/bash -x
+# $Id$
+## @file
+# Script for test building the VirtualBox kernel modules against a kernel.
+#
+# This script assumes the kernel directory it is pointed to was prepared using
+# build-kernel.sh, as that script plants a couple of files and symlinks needed
+# by this script.
+#
+
+#
+# Copyright (C) 2019 Oracle Corporation
+#
+# This file is part of VirtualBox Open Source Edition (OSE), as
+# available from http://www.virtualbox.org. This file is free software;
+# you can redistribute it and/or modify it under the terms of the GNU
+# General Public License (GPL) as published by the Free Software
+# Foundation, in version 2 as it comes in the "COPYING" file of the
+# VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+# hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+#
+
+if [ $# -lt 2 ]; then
+    echo "usage: modules.sh <PATH_STAGE> <kernel-dir>"
+    exit 2
+fi
+PATH_STAGE=$1
+PATH_STAGE_GUEST_SRC="${PATH_STAGE}/bin/additions/src"
+PATH_STAGE_HOST_SRC="${PATH_STAGE}/bin/src"
+KERN_DIR=$2
+KERN_NAME=`basename "${KERN_DIR}"`
+KERN_VER=`echo ${KERN_NAME} | sed -e 's/^.*linux-//'`
+KERN_BASE_DIR=`dirname "${KERN_DIR}"`
+BLDDIR_BASE="/tmp/modbld"
+BLDDIR="${BLDDIR_BASE}/`echo ${PATH_STAGE} ${KERN_BASE_DIR} | sha1sum | cut -b1-16`-${KERN_NAME}/"
+JOBS=36
+shift
+shift
+
+
+# Process other options
+OPT_CLOBBER=
+while [ $# -gt 0 ];
+do
+    case "$1" in
+        clobber) OPT_CLOBBER=1;;
+        --version) KERN_VER="$2"; shift;;
+        *)  echo "syntax error: $1" 1>&2
+            exit 2;;
+    esac
+    shift;
+done
+
+#
+# Prepare the sources we're to build.
+#
+set -e
+test -n "${BLDDIR}"
+if [ -d "${BLDDIR}" -a -n "${OPT_CLOBBER}" ]; then
+    rm -R "${BLDDIR}/"
+fi
+
+mkdir -p "${BLDDIR}/" "${BLDDIR}/guest/" "${BLDDIR}/host/"
+rsync -crlDp --exclude="*.tmp_versions/" --include="*/" --include="*.h" --include="*.c" --include="*.cpp" --include="Makefile*" --include="build_in_tmp" --exclude="*" "${PATH_STAGE_HOST_SRC}/"  "${BLDDIR}/host/"
+rsync -crlDp --exclude="*.tmp_versions/" --include="*/" --include="*.h" --include="*.c" --include="*.cpp" --include="Makefile*" --include="build_in_tmp" --exclude="*" "${PATH_STAGE_GUEST_SRC}/" "${BLDDIR}/guest/"
+
+#
+# Do the building.
+#
+if [ -f "${KERN_DIR}/.bird-make" -a ! -f "${KERN_DIR}/.bird-failed" ]; then
+    if "${KERN_DIR}/.bird-make" --help 2>&1 | grep -q output-sync -; then
+        SYNC_OUTPUT="--output-sync=target"
+    else
+        SYNC_OUTPUT=""
+    fi
+    "${KERN_DIR}/.bird-make" -C "${BLDDIR}/guest/" \
+        VBOX_NOJOBS=1 -j${JOBS} `cat "${KERN_DIR}/.bird-overrides"` ${SYNC_OUTPUT} "KERN_DIR=${KERN_DIR}" "KERN_VER=${KERN_VER}"
+    case "${KERN_VER}" in
+        [3-9].*|2.6.3[789]*) ## todo fix this so it works back to 2.6.18 (-fno-pie, -Wno-declaration-after-statement)
+            "${KERN_DIR}/.bird-make" -C "${BLDDIR}/host/"  \
+                VBOX_NOJOBS=1 -j${JOBS} `cat "${KERN_DIR}/.bird-overrides"` ${SYNC_OUTPUT} "KERN_DIR=${KERN_DIR}" "KERN_VER=${KERN_VER}"
+            ;;
+    esac
+else
+    echo "${KERN_DIR}: Skipping..."
+fi
+