Added functionality to apply custom patch files during building

Usefull  to patch existing libraries

pio-scripts/patch_apply.py

@@ -0,0 +1,78 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Copyright (C) 2023 Thomas Basler and others
+#
+import os
+import subprocess
+import re
+
+Import("env")
+
+def getPatchPath(env):
+    return os.path.join(env["PROJECT_DIR"], "patches", env.GetProjectOption('custom_patches'))
+
+def is_tool(name):
+    """Check whether `name` is on PATH and marked as executable."""
+
+    # from whichcraft import which
+    from shutil import which
+
+    return which(name) is not None
+
+def replaceInFile(in_file, out_file, text, subs, flags=0):
+    """
+        Function for replacing content for the given file
+        Taken from https://www.studytonight.com/python-howtos/search-and-replace-a-text-in-a-file-in-python
+    """
+    if os.path.exists(in_file):
+        with open(in_file, "rb") as infile:
+            with open(out_file, "wb") as outfile:
+                #read the file contents
+                file_contents = infile.read()
+                text_pattern = re.compile(re.escape(text), flags)
+                file_contents = text_pattern.sub(subs, file_contents.decode('utf-8'))
+                outfile.seek(0)
+                outfile.truncate()
+                outfile.write(file_contents.encode())
+
+def main():
+    if (env.GetProjectOption('custom_patches', '') == ''):
+        print('No custom_patches specified')
+        return
+
+    if (not is_tool('git')):
+        print('Git not found. Will not apply custom patches!')
+        return
+
+    directory = getPatchPath(env)
+    if (not os.path.isdir(directory)):
+        print('Patch directory not found: ' + directory)
+        return
+
+    for file in os.listdir(directory):
+        if (not file.endswith('.patch')):
+            continue
+
+        fullPath = os.path.join(directory, file)
+        preparePath = fullPath + '.prepare'
+        replaceInFile(fullPath, preparePath, '$$$env$$$', env['PIOENV'])
+        print('Working on patch: ' + fullPath + '... ', end='')
+
+        # Check if patch was already applied
+        process = subprocess.run(['git', 'apply', '--reverse', '--check', preparePath], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        if (process.returncode == 0):
+            print('already applied')
+            os.remove(preparePath)
+            continue
+
+        # Apply patch
+        process = subprocess.run(['git', 'apply', preparePath])
+        if (process.returncode == 0):
+            print('applied')
+        else:
+            print('failed')
+
+        os.remove(preparePath)
+
+
+main()