Fix packaging issues

* Bzip2 was manually installed directly into filesystem, so bzip2 package was empty.
  Fixed by installing it to destdir. bzip2 moves out its binary before installing
  its own package.
* sha256sum from stage0-posix was not checking any checksums because it does not
  accept piped input. Fixed by using temporary file.
* grep was broken for a short time (but with fixed bzip2 package this caused failures)
  due to touch creating grep file of zero size (egrep symlink was touched).
  Fixed by implementing touch -h

Resolves #156, resolves #166, resolves #167

sysc/init

@@ -9,6 +9,12 @@ set -e
 # shellcheck source=sysa/helpers.sh
 . helpers.sh
 
+export PATH=/usr/bin:/usr/sbin
+export PREFIX=/usr
+export SOURCES=/usr/src
+export DESTDIR=/tmp/destdir
+export DISTFILES=/distfiles
+
 echo
 echo "Installing packages into sysc"
 

sysc/run.sh

@@ -11,12 +11,6 @@ set -e
 # shellcheck source=sysa/helpers.sh
 . helpers.sh
 
-export PATH=/usr/bin:/usr/sbin
-export PREFIX=/usr
-export SOURCES=/usr/src
-export DESTDIR=/tmp/destdir
-export DISTFILES=/distfiles
-
 create_fhs() {
     # Add the rest of the FHS that we will use and is not created pre-boot
     rm -rf /sbin /usr/sbin
@@ -24,7 +18,7 @@ create_fhs() {
     for d in bin lib sbin; do
         ln -s "usr/${d}" "/${d}"
     done
-    mkdir /etc /proc /run /sys /tmp /var
+    mkdir -p /etc /proc /run /sys /tmp /var
     mount -t proc proc /proc
     mount -t sysfs sysfs /sys
     # Make /tmp a ramdisk (speeds up configure etc significantly)
@@ -37,4 +31,4 @@ create_fhs
 
 build bash-5.1
 
-exec env -i PATH=${PATH} PREFIX=${PREFIX} SOURCES=${SOURCES} DESTDIR=${DESTDIR} DISTFILES=${DISTFILES} bash run2.sh
+exec env -i PATH="${PATH}" PREFIX="${PREFIX}" SOURCES="${SOURCES}" DESTDIR="${DESTDIR}" DISTFILES="${DISTFILES}" bash run2.sh