Jamulus.pro: Implement (n)make clang_format

This simplifies submission of properly formatted code for users
with no editor/IDE integration of clang-format (jamulussoftware#1702).

Author: hoffie

.clang-format-ignore

@@ -1,3 +1,7 @@
-# exclude third party code from clang-format checks
+# Exclude third party code from clang-format checks.
+#
+# This file is used by the clang-format-lint-action on Github.
+# When updating this list, remember to update Jamulus.pro's CLANG_SOURCES
+# as well.
 ./libs
 ./windows/nsProcess

.github/workflows/coding-style-check.yml

@@ -17,4 +17,6 @@ jobs:
     - uses: DoozyX/clang-format-lint-action@2a28e3a8d9553f244243f7e1ff94f6685dff87be
       with:
         clangFormatVersion: 10
+        # When updating the extension list, remember to update
+        # Jamulus.pro's CLANG_SOURCES as well.
         extensions: 'cpp,h'

Jamulus.pro

@@ -1169,3 +1169,11 @@ contains(CONFIG, "disable_version_check") {
 
 ANDROID_ABIS = armeabi-v7a arm64-v8a x86 x86_64
 
+# Enable formatting all code via `make clang_format`.
+# Note: When extending the list of file extensions or when adding new code directories,
+# be sure to update .github/workflows/coding-style-check.yml and .clang-format-ignore as well.
+CLANG_FORMAT_SOURCES = $$files(*.cpp, true) $$files(*.h, true)
+CLANG_FORMAT_SOURCES = $$find(CLANG_FORMAT_SOURCES, ^\(android|ios|mac|linux|src|windows\)/)
+CLANG_FORMAT_SOURCES ~= s!^\(windows/nsProcess/|src/res/qrc_resources\.cpp\)\S*$!!g
+clang_format.commands = 'clang-format -i $$CLANG_FORMAT_SOURCES'
+QMAKE_EXTRA_TARGETS += clang_format