niminst: remove complex non-posix line noise for install.tmpl

tools/niminst/install.tmpl

@@ -3,35 +3,7 @@
 #  result = "#! /bin/sh\n# Generated by niminst\n"
 #  var proj = c.name.toLowerAscii
 
-## Current directory you start script from
-BASE_DIR=$(pwd)
-
-## The following one-liner takes directory path which contains install script.
-## `command -v -- "$0"` takes path if script sourced from interactive shell
-## `dirname` returns relative directory path to install script
-## `cd -P` dive into directory to use `pwd`
-## `pwd -P` prints full path to install script directory path
-## -P option allows to use symlinks in path
-## Good explanation can be found here:
-## http://stackoverflow.com/questions/29832037/how-to-get-script-directory-in-posix-sh
-NIM_DIR=$(cd -P -- "$(dirname -- "$(command -v -- "$0")")" && pwd -P)
-
-go_back() {
-  cd $BASE_DIR
-}
-
-## Go to base dir on exit
-trap go_back EXIT
-
-install_error() {
-  echo "Nim installation failed!"
-  exit 1
-}
-
-## Exit if any command failed
-trap install_error ERR ## `set -e` alternative
-
-cd $NIM_DIR
+set -e
 
 if [ $# -eq 1 ] ; then
 # if c.cat[fcUnixBin].len > 0: