Add .clang-format file

And a Makefile target to format uncommitted code.

Unfortunately clang-format seems to be too strict with indenting, and I
does not work well with C99 designated initializers.

I want to start to use it manually for new code and see if that is
useful or not.

.clang-format

@@ -0,0 +1,33 @@
+# Style for goxel.
+# Still a work in progress.
+
+BasedOnStyle: LLVM
+
+AllowShortFunctionsOnASingleLine: Empty
+AllowShortIfStatementsOnASingleLine: WithoutElse
+
+ColumnLimit: 80
+PenaltyExcessCharacter: 1000
+
+# Never use tabs for indentation.
+UseTab: Never
+TabWidth: 4
+IndentWidth: 4
+
+ContinuationIndentWidth: 8
+BracedInitializerIndentWidth: 4
+
+BreakBeforeBraces: Linux
+
+BinPackParameters: false
+AllowAllArgumentsOnNextLine: true
+
+SortIncludes: true
+
+PenaltyReturnTypeOnItsOwnLine: 10000
+PenaltyBreakAssignment: 100
+PenaltyIndentedWhitespace: 2
+
+ForEachMacros:
+  - DL_FOREACH
+  - DL_FOREACH_SAFE

Makefile

@@ -7,7 +7,7 @@ endif
 
 .ONESHELL:
 
-all:
+all: .FORCE
 	scons $(JOBS)
 
 release:
@@ -19,12 +19,17 @@ profile:
 run:
 	./goxel
 
-clean:
+clean: .FORCE
 	scons -c
 
 analyze:
 	scan-build scons mode=analyze
 
+# For the moment only apply the format to uncommited changes.
+format: .FORCE
+	git clang-format -f
+
+
 # Generate an AppImage.  Used by github CI.
 appimage:
 	scons mode=release
@@ -63,3 +68,7 @@ uninstall:
 	rm -f $(DESTDIR)$(PREFIX)/share/applications/goxel.desktop
 	rm -f $$(printf '%s%s' $(DESTDIR)$(PREFIX)/share/metainfo/ \
 	         io.github.guillaumechereau.Goxel.metainfo.xml)
+
+.PHONY: all
+
+.FORCE: