scripts: consolidate code to find bitbake path

Several of these scripts were using duplicated code (and slightly
different methods) to find the path to bitbake and add its lib
subdirectory to the Python import path. Add some common code to do this
and change the scripts to use it.

Fixes [YOCTO #5076].

(From OE-Core rev: 0b5e94e168819134dcda0433c8ae893df4ab13ce)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/contrib/list-packageconfig-flags.py

@@ -23,26 +23,19 @@ import sys
 import getopt
 import os
 
-def search_bitbakepath():
-    bitbakepath = ""
 
-    # Search path to bitbake lib dir in order to load bb modules
-    if os.path.exists(os.path.join(os.path.dirname(sys.argv[0]), '../../bitbake/lib/bb')):
-        bitbakepath = os.path.join(os.path.dirname(sys.argv[0]), '../../bitbake/lib')
-        bitbakepath = os.path.abspath(bitbakepath)
-    else:
-        # Look for bitbake/bin dir in PATH
-        for pth in os.environ['PATH'].split(':'):
-            if os.path.exists(os.path.join(pth, '../lib/bb')):
-                bitbakepath = os.path.abspath(os.path.join(pth, '../lib'))
-                break
-        if not bitbakepath:
-            sys.stderr.write("Unable to find bitbake by searching parent directory of this script or PATH\n")
-            sys.exit(1)
-    return bitbakepath
+scripts_path = os.path.abspath(os.path.dirname(os.path.abspath(sys.argv[0])))
+lib_path = os.path.abspath(scripts_path + '/../lib')
+sys.path = sys.path + [lib_path]
+
+import scriptpath
 
 # For importing the following modules
-sys.path.insert(0, search_bitbakepath())
+bitbakepath = scriptpath.add_bitbake_lib_path()
+if not bitbakepath:
+    sys.stderr.write("Unable to find bitbake by searching parent directory of this script or PATH\n")
+    sys.exit(1)
+
 import bb.cache
 import bb.cooker
 import bb.providers