Configure Linux out of source tree

That will make sure that we will not leave source directory in configured
state, so other users who want to configure it out of tree will not get an
error. If source directory already configured, then we use it as is.

Signed-off-by: Anton Kolesov <[email protected]>

Author: anthony-kolesov

ChangeLog

@@ -1,3 +1,7 @@
+2015-02-27  Anton Kolesov  <[email protected]>
+
+	* build-uclibc.sh: Configure linux out of source tree.
+
 2015-02-27  Anton Kolesov  <[email protected]>
 
 	* build-cleanup.sh: Refresh.

build-uclibc.sh

@@ -205,7 +205,8 @@ echo "START ${ARC_ENDIAN}-endian uClibc: $(date)" | tee -a ${logfile}
 # Initalize, including getting the tool versions.
 . "${ARC_GNU}"/toolchain/arc-init.sh
 uclibc_build_dir="$(echo "${PWD}")"/uClibc
-linux_build_dir=${LINUXDIR}
+linux_src_dir=${LINUXDIR}
+linux_build_dir=$build_dir/linux
 
 # If PDF docs are enabled, then check if prerequisites are satisfied.
 if [ "x${DO_PDF}" = "x--pdf" ]
@@ -243,14 +244,25 @@ mkdir -p "$build_dir"
 echo "Installing Linux headers ..." | tee -a "${logfile}"
 echo "============================" >> "${logfile}"
 
-cd "${linux_build_dir}"
-
-# Configure Linux if not already
+cd "${linux_src_dir}"
+
+# It would be irresponsible for us to configure linux in source tree and leave
+# it at that, because if anybody else after that would try to configure/build
+# linux out-of-tree they will fail - Linux cannot configure out of tree when it
+# is already configured in tree. So we need to either clean configuration after
+# installing headers or just  configure out of tree ourself. Second options
+# seems like more solid solution. However it will fail if Linux already has
+# been configured. Bam! In that case we just use Linux as-is. All of that is
+# mildly complex but this approach makes sure that this script is a friendly
+# neighbor and doesn't pollute in many places.
 if [ ! -f .config ]
 then
-    if make ARCH=${arch} defconfig >> "${logfile}" 2>&1
+    # Linux makefile expects this directory to exist.
+    mkdir -p "$linux_build_dir"
+    if make ARCH=arc defconfig O="$linux_build_dir" >> "${logfile}" 2>&1
     then
 	echo "  finished configuring Linux"
+	cd "$linux_build_dir"
     else
 	echo "ERROR: Linux configuration was not successful. Please"
 	echo "       see \"${logfile}\" for details."
@@ -260,7 +272,9 @@ else
     echo "  Linux already configured"
 fi
 
-if make ARCH=${arch} INSTALL_HDR_PATH=${SYSROOTDIR}/usr \
+# Wherever linux has been configured in or out of tree, at this stage we are in
+# the directory with .config file.
+if make ARCH=arc INSTALL_HDR_PATH=${SYSROOTDIR}/usr \
     headers_install >> "${logfile}" 2>&1
 then
     echo "  finished installing Linux headers"