Fix setting $PS1 for bash

And let user know how to set prompt for zsh and powerline in our
README.

README.md

@@ -40,3 +40,32 @@ If your operating system handles symlinks, built modules source code will be ava
 at the root of `gst-build/` for example GStreamer core will be in `gstreamer/`. Otherwise
 they will be present in `subprojects/`. You can simply hack in there and to rebuild you
 just need to rerun `ninja -C build/`.
+
+
+## Add information about GStreamer development environment in your prompt line
+
+### Bash prompt
+
+We automatically handle `bash` and set `$PS1` accordingly
+
+### Zsh prompt
+
+In your `.zshrc`, you should add something like:
+
+```
+export PROMPT="$GST_ENV-$PROMPT"
+```
+
+### Using powerline
+
+In your powerline theme configuration file (by default in
+`{POWERLINE INSTALLATION DIR}/config_files/themes/shell/default.json`)
+you should add a new environment segment as follow:
+
+```
+{
+  "function": "powerline.segments.common.env.environment",
+  "args": { "variable": "GST_ENV" },
+  "priority": 50
+},
+```

gst-uninstalled.py

@@ -4,7 +4,9 @@ import argparse
 import os
 import re
 import site
+import shutil
 import subprocess
+import tempfile
 
 
 SCRIPTDIR = os.path.abspath(os.path.dirname(__file__))
@@ -15,16 +17,6 @@ def prepend_env_var(env, var, value):
     env[var] = env[var].replace(os.pathsep + os.pathsep, os.pathsep).strip(os.pathsep)
 
 
-def set_prompt_var(options, env):
-    ps1 = env.get("PS1")
-    if ps1:
-        env["PS1"] = "[gst-%s] %s" % (options.gst_version, ps1)
-
-    prompt = env.get("PROMPT")
-    if prompt:
-        env["PROMPT"] = "[gst-%s] %s" % (options.gst_version, prompt)
-
-
 def get_subprocess_env(options):
     env = os.environ.copy()
 
@@ -56,6 +48,7 @@ def get_subprocess_env(options):
     prepend_env_var(env, "PATH", os.path.join(SCRIPTDIR, 'meson'))
     env["PATH"] += os.pathsep + PATH
     env["GST_VERSION"] = options.gst_version
+    env["GST_ENV"] = 'gst-' + options.gst_version
     env["GST_PLUGIN_SYSTEM_PATH"] = ""
     env["GST_PLUGIN_SCANNER"] = os.path.normpath(
         "%s/subprojects/gstreamer/libs/gst/helpers/gst-plugin-scanner" % options.builddir)
@@ -89,9 +82,6 @@ def get_subprocess_env(options):
                 if has_typelib:
                     break
 
-
-    set_prompt_var(options, env)
-
     return env
 
 
@@ -115,8 +105,17 @@ if __name__ == "__main__":
             args = [os.environ.get("COMSPEC", r"C:\WINDOWS\system32\cmd.exe")]
         else:
             args = [os.environ.get("SHELL", os.path.realpath("/bin/sh"))]
-        if args[0] == "/bin/bash":
-            args.append("--noprofile")
+        if "bash" in args[0]:
+            bashrc = os.path.expanduser('~/.bashrc')
+            if os.path.exists(bashrc):
+                tmprc = tempfile.NamedTemporaryFile(mode='w')
+                with open(bashrc, 'r') as src:
+                    shutil.copyfileobj(src, tmprc)
+                tmprc.write('\nexport PS1="[gst-%s] $PS1"' % options.gst_version)
+                tmprc.flush()
+                # Let the GC remove the tmp file
+                args.append("--rcfile")
+                args.append(tmprc.name)
 
     try:
         exit(subprocess.call(args, env=get_subprocess_env(options)))