diff --git a/GNUmakefile b/GNUmakefile
index c7807720cb9..6e3e3cde5e8 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -237,26 +237,42 @@ test_deprecated:
 
 test_style_c:
 	# run our own checks on C/C++ style
-	PYTHONIOENCODING=utf_8 python3 "$(BLENDER_DIR)/source/tools/check_source/check_style_c.py" "$(BLENDER_DIR)/source/blender" "$(BLENDER_DIR)/source/creator" --no-length-check
+	PYTHONIOENCODING=utf_8 python3 \
+	    "$(BLENDER_DIR)/source/tools/check_source/check_style_c.py" \
+	    "$(BLENDER_DIR)/source/blender" \
+	    "$(BLENDER_DIR)/source/creator" \
+	    --no-length-check
 
 test_style_c_qtc:
 	# run our own checks on C/C++ style
 	USE_QTC_TASK=1 \
-	PYTHONIOENCODING=utf_8 python3 "$(BLENDER_DIR)/source/tools/check_source/check_style_c.py" "$(BLENDER_DIR)/source/blender" "$(BLENDER_DIR)/source/creator" --no-length-check > \
-	test_style.tasks
+	PYTHONIOENCODING=utf_8 python3 \
+	    "$(BLENDER_DIR)/source/tools/check_source/check_style_c.py" \
+	    "$(BLENDER_DIR)/source/blender" \
+	    "$(BLENDER_DIR)/source/creator" \
+	    --no-length-check \
+	    > \
+	    "$(BLENDER_DIR)/test_style.tasks"
 	@echo "written: test_style.tasks"
 
 
 test_style_osl:
 	# run our own checks on C/C++ style
-	PYTHONIOENCODING=utf_8 python3 "$(BLENDER_DIR)/source/tools/check_source/check_style_c.py" "$(BLENDER_DIR)/intern/cycles/kernel/shaders" "$(BLENDER_DIR)/release/scripts/templates_osl"
+	PYTHONIOENCODING=utf_8 python3 \
+	    "$(BLENDER_DIR)/source/tools/check_source/check_style_c.py" \
+	    "$(BLENDER_DIR)/intern/cycles/kernel/shaders" \
+	    "$(BLENDER_DIR)/release/scripts/templates_osl"
 
 
 test_style_osl_qtc:
 	# run our own checks on C/C++ style
 	USE_QTC_TASK=1 \
-	PYTHONIOENCODING=utf_8 python3 "$(BLENDER_DIR)/source/tools/check_source/check_style_c.py" "$(BLENDER_DIR)/intern/cycles/kernel/shaders" "$(BLENDER_DIR)/release/scripts/templates_osl" > \
-	test_style.tasks
+	PYTHONIOENCODING=utf_8 python3 \
+	    "$(BLENDER_DIR)/source/tools/check_source/check_style_c.py" \
+	    "$(BLENDER_DIR)/intern/cycles/kernel/shaders" \
+	    "$(BLENDER_DIR)/release/scripts/templates_osl" \
+	    > \
+	    "$(BLENDER_DIR)/test_style.tasks"
 	@echo "written: test_style.tasks"
 
 # -----------------------------------------------------------------------------
@@ -281,7 +297,7 @@ check_cppcheck:
 	$(CMAKE_CONFIG)
 	cd "$(BUILD_DIR)" ; \
 	python3 "$(BLENDER_DIR)/build_files/cmake/cmake_static_check_cppcheck.py" 2> \
-	"$(BLENDER_DIR)/check_cppcheck.txt"
+	    "$(BLENDER_DIR)/check_cppcheck.txt"
 	@echo "written: check_cppcheck.txt"
 
 check_clang_array:
@@ -306,22 +322,39 @@ check_smatch:
 
 check_spelling_py:
 	cd "$(BUILD_DIR)" ; \
-	PYTHONIOENCODING=utf_8 python3 "$(BLENDER_DIR)/source/tools/check_source/check_spelling.py" "$(BLENDER_DIR)/release/scripts"
+	PYTHONIOENCODING=utf_8 python3 \
+	    "$(BLENDER_DIR)/source/tools/check_source/check_spelling.py" \
+	    "$(BLENDER_DIR)/release/scripts"
 
 check_spelling_c:
 	cd "$(BUILD_DIR)" ; \
-	PYTHONIOENCODING=utf_8 python3 "$(BLENDER_DIR)/source/tools/check_source/check_spelling.py" "$(BLENDER_DIR)/source"
+	PYTHONIOENCODING=utf_8 python3 \
+	    "$(BLENDER_DIR)/source/tools/check_source/check_spelling.py" \
+	    "$(BLENDER_DIR)/source" \
+	    "$(BLENDER_DIR)/intern/cycles" \
+	    "$(BLENDER_DIR)/intern/guardedalloc" \
+	    "$(BLENDER_DIR)/intern/ghost" \
 
 check_spelling_c_qtc:
 	cd "$(BUILD_DIR)" ; USE_QTC_TASK=1 \
-	PYTHONIOENCODING=utf_8 python3 "$(BLENDER_DIR)/source/tools/check_source/check_spelling.py" "$(BLENDER_DIR)/source" > \
-	"$(BLENDER_DIR)/check_spelling_c.tasks"
+	PYTHONIOENCODING=utf_8 python3 \
+	    "$(BLENDER_DIR)/source/tools/check_source/check_spelling.py" \
+	    "$(BLENDER_DIR)/source" \
+	    "$(BLENDER_DIR)/intern/cycles" \
+	    "$(BLENDER_DIR)/intern/guardedalloc" \
+	    "$(BLENDER_DIR)/intern/ghost" \
+	    > \
+	    "$(BLENDER_DIR)/check_spelling_c.tasks"
 
 check_spelling_osl:
-	cd "$(BUILD_DIR)" ; PYTHONIOENCODING=utf_8 python3 "$(BLENDER_DIR)/source/tools/check_source/check_spelling.py" "$(BLENDER_DIR)/intern/cycles/kernel/shaders"
+	cd "$(BUILD_DIR)" ;\
+	PYTHONIOENCODING=utf_8 python3 \
+	    "$(BLENDER_DIR)/source/tools/check_source/check_spelling.py" \
+	    "$(BLENDER_DIR)/intern/cycles/kernel/shaders"
 
 check_descriptions:
-	"$(BUILD_DIR)/bin/blender" --background -noaudio --factory-startup --python "$(BLENDER_DIR)/source/tools/check_source/check_descriptions.py"
+	"$(BUILD_DIR)/bin/blender" --background -noaudio --factory-startup --python \
+	    "$(BLENDER_DIR)/source/tools/check_source/check_descriptions.py"
 
 # -----------------------------------------------------------------------------
 # Utilities