To rebuild to the toolchain:

Clone the buildroot depot:
   git://git.buildroot.net/buildroot

Run make menuconfig and disable everything except building the toolchain, or
just use this as your .config in the buildroot directory

---------------------- .config ---------------------
BR2_arm=y
BR2_cortex_a9=y
BR2_ARM_ENABLE_NEON=y
BR2_ARM_FPU_VFPV3=y
BR2_KERNEL_HEADERS_3_2=y
BR2_TOOLCHAIN_BUILDROOT_GLIBC=y
BR2_GCC_VERSION_4_9_X=y
BR2_TOOLCHAIN_BUILDROOT_CXX=y
# BR2_TARGET_GENERIC_GETTY is not set
# BR2_TARGET_GENERIC_REMOUNT_ROOTFS_RW is not set
BR2_PACKAGE_MAKE=y
# BR2_TARGET_ROOTFS_TAR is not set
----------------------------------------------------


-- Next apply this patch to make all of the host build statically
   to remove dependence on locally generated shared libs.

----------------------------------------------------------------------
From 39c92fa91756747fa8eaf1fc898214658d1f8451 Mon Sep 17 00:00:00 2001
From: John Newlin <jnewlin@google.com>
Date: Fri, 3 Oct 2014 21:58:51 -0700
Subject: [PATCH] Build libraries statically to make hermetic builds work.

---
 package/pkg-autotools.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/pkg-autotools.mk b/package/pkg-autotools.mk
index 4404f15..e4e4df9 100644
--- a/package/pkg-autotools.mk
+++ b/package/pkg-autotools.mk
@@ -165,7 +165,7 @@ define $(2)_CONFIGURE_CMDS
                ./configure \
                --prefix="$$(HOST_DIR)/usr" \
                --sysconfdir="$$(HOST_DIR)/etc" \
-               --enable-shared --disable-static \
+               --disable-shared --enable-static \
                --disable-gtk-doc \
                --disable-doc \
                --disable-docs \
-- 
2.1.0.rc2.206.gedb03e5
----------------------------------------------------------------------

Run 'make'  (go grab some coffee this will take awhile)


--
rm -rf *
cp -prf <path to output>
git add -A
git commit