kernel/linux: fix using custom location

Currently, extract and patch are skipped as thus:
- using a custom directory of pre-installed headers
- a correctly named directory already exists

Otherwise, extract and patch are done.

The current second condition is wrong, because it allows the following
sequence to happen:
- a non-custom kernel is used
- a previous build only partially extracted the non-custom sources
- that p[revious build broke during extraction (eg. incomplete tarball...)
- a subsequent build will find a properly named directory, and will
thus skip extract and patch, which is wrong

Fix that by following the conditions in this table:

Type | Extract | Patch
----------------------+---------+-------
Pre-installed headers | N | N
custom directory | N | N
custom tarball | Y | N
mainstream tarball | Y | Y

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: David Holsgrove <david.holsgrove@xilinx.com>

 From 323453d85ed29ccba7a81d884479188869cd64b7 Mon Sep 17 00:00:00 2001

 From: Henning Heinold <heinold@inf.fu-berlin.de>

 Date: Sat, 23 Jan 2010 21:29:42 -0800

 Subject: [PATCH 13/15] Makefile.in: Make install_dev depend on install_runtime.

 * Helps in parallel build.

 Signed-off-by: Henning Heinold <heinold@inf.fu-berlin.de>

 Signed-off-by: Khem Raj <raj.khem@gmail.com>

 Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

 ---

  Makefile.in |    2 +-

  1 files changed, 1 insertions(+), 1 deletions(-)

 diff --git a/Makefile.in b/Makefile.in

 index ec4c28e..a889838 100644

 --- a/Makefile.in

 +++ b/Makefile.in

 @@ -370,7 +370,7 @@ ifneq ($(UCLIBC_SUPPORT_AI_ADDRCONFIG),y)

  endif

  # Installs development library links.

 -install_dev: install_headers all

 +install_dev: install_headers install_runtime

  	$(INSTALL) -d $(PREFIX)$(DEVEL_PREFIX)lib

  	-$(INSTALL) -m 644 lib/*.[ao] $(PREFIX)$(DEVEL_PREFIX)lib/

  ifeq ($(HAVE_SHARED),y)

 -- 

 1.6.6.1