Changed "realpath" in the scripts (added from a pull request merge

earlier today) to "readlink -f", because "realpath" does not exist
on some systems (e.g., CentOS).  "readlink" seems to be more
universally available.  Noticed that the ext2spice and ext2sim
scripts use /bin/sh instead of /bin/bash, which would cause problems
with some systems where sh != bash.

tcltk/ext2sim.sh.in

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 #
 # Standalone script for ext2sim, for Tcl-based magic 8.0
 #
@@ -18,7 +18,7 @@ TCL_REL_OR_ABS=TCL_DIR_REL_OR_ABS
 if [ "${TCL_REL_OR_ABS:0:1}" = "/" ]; then
    TCL_DIR=$TCL_REL_OR_ABS
 else
-   TCL_DIR=$(dirname $(realpath ${BASH_SOURCE[0]}))/$TCL_REL_OR_ABS
+   TCL_DIR=$(dirname $(readlink -f ${BASH_SOURCE[0]}))/$TCL_REL_OR_ABS
 fi
 #
 eval ${TCL_DIR}/magicdnull -dnull -noconsole -nowrapper $mgargs <<EOF

tcltk/ext2spice.sh.in

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 #
 # Standalone script for ext2spice, for Tcl-based magic 8.0
 #
@@ -18,7 +18,7 @@ TCL_REL_OR_ABS=TCL_DIR_REL_OR_ABS
 if [ "${TCL_REL_OR_ABS:0:1}" = "/" ]; then
    TCL_DIR=$TCL_REL_OR_ABS
 else
-   TCL_DIR=$(dirname $(realpath ${BASH_SOURCE[0]}))/$TCL_REL_OR_ABS
+   TCL_DIR=$(dirname $(readlink -f ${BASH_SOURCE[0]}))/$TCL_REL_OR_ABS
 fi
 #
 eval ${TCL_DIR}/magicdnull -dnull -noconsole -nowrapper $mgargs <<EOF

tcltk/magic.sh.in

@@ -15,7 +15,7 @@ TCL_REL_OR_ABS=TCL_DIR_REL_OR_ABS
 if [ "${TCL_REL_OR_ABS:0:1}" = "/" ]; then
    TCL_DIR=$TCL_REL_OR_ABS
 else
-   TCL_DIR=$(dirname $(realpath ${BASH_SOURCE[0]}))/$TCL_REL_OR_ABS
+   TCL_DIR=$(dirname $(readlink -f ${BASH_SOURCE[0]}))/$TCL_REL_OR_ABS
 fi
 TKCON=true
 DNULL=