make: split off license extraction

As an intermediate measure improving build times with multiple jobs
until the toplevel Makefile can properly handle parallelism.

Author: TheOneric

Makefile

@@ -205,36 +205,9 @@ dist/js/subtitles-octopus.js: dist/license/all src/subtitles-octopus.js
 	mkdir -p dist/js
 	awk '1 {print "// "$$0}' dist/license/all | cat - src/subtitles-octopus.js > $@
 
-LIB_LICENSES := brotli expat freetype fribidi fontconfig harfbuzz libass
-LIB_LICENSES_FINDOPT_brotli   := -path ./research -prune -false -o ! -path ./js/decode.min.js
-LIB_LICENSES_FINDOPT_expat    := -path ./expat/fuzz -prune -false -o
-LIB_LICENSES_FINDOPT_freetype := -path ./src/tools -prune -false -o
-LIB_LICENSES_FINDOPT_fribidi  := -path ./bin -prune -false -o
-LIB_LICENSES_FINDOPT_harfbuzz := -path ./test -prune -false -o
-
-$(addprefix dist/license/, $(LIB_LICENSES)): dist/license/%: .git/modules/lib/%/HEAD build/license_extract.sh build/license_defaults
-	@mkdir -p dist/license
-	(cd "lib/$*" && FINDOPTS="$(LIB_LICENSES_FINDOPT_$*)" \
-	 ../../build/license_extract.sh ../../build/license_defaults "$*"  .) > $@
-
-dist/license/subtitlesoctopus: .git/HEAD build/license_extract.sh
-	@mkdir -p dist/license
-	build/license_extract.sh build/license_defaults subtitlesoctopus src > dist/license/subtitlesoctopus
-
-dist/license/all: dist/license/subtitlesoctopus $(addprefix dist/license/, $(LIB_LICENSES)) build/license_fullnotice build/license_lint.awk
-	@echo "# The following lists all copyright notices and licenses for the" >  dist/license/all
-	@echo "# work contained in JavascriptSubtitlesOctopus per project."      >> dist/license/all
-	@echo "" >> dist/license/all
-
-	@echo "Concatenate extracted license info..."
-	@$(foreach LIB_PROJ, subtitlesoctopus $(LIB_LICENSES), \
-		echo "# Project: $(LIB_PROJ)"  >> dist/license/all && \
-		cat  dist/license/$(LIB_PROJ)  >> dist/license/all && \
-	) :
-
-	mv dist/license/all dist/license/all.tmp
-	build/license_lint.awk dist/license/all.tmp build/license_fullnotice
-	cat dist/license/all.tmp build/license_fullnotice > dist/license/all
+dist/license/all:
+	@#FIXME: allow -j in toplevel Makefile and reintegrate licence extraction into this file
+	make -j "$$(nproc)" -f Makefile_licence all
 
 dist/js/COPYRIGHT: dist/license/all
 	cp "$<" "$@"

Makefile_licence

@@ -0,0 +1,39 @@
+# FIXME: temporarily split Makefile to parallelise licence info extraction
+#        once -j can be passed to the toplevel Makefile this should be moved
+#        back into the main Makefile
+
+all: dist/license/all
+
+LIB_LICENSES := brotli expat freetype fribidi fontconfig harfbuzz libass
+LIB_LICENSES_FINDOPT_brotli   := -path ./research -prune -false -o ! -path ./js/decode.min.js
+LIB_LICENSES_FINDOPT_expat    := -path ./expat/fuzz -prune -false -o
+LIB_LICENSES_FINDOPT_freetype := -path ./src/tools -prune -false -o
+LIB_LICENSES_FINDOPT_fribidi  := -path ./bin -prune -false -o
+LIB_LICENSES_FINDOPT_harfbuzz := -path ./test -prune -false -o
+
+$(addprefix dist/license/, $(LIB_LICENSES)): dist/license/%: .git/modules/lib/%/HEAD build/license_extract.sh build/license_defaults
+	@mkdir -p dist/license
+	(cd "lib/$*" && FINDOPTS="$(LIB_LICENSES_FINDOPT_$*)" \
+	 ../../build/license_extract.sh ../../build/license_defaults "$*"  .) > $@
+
+dist/license/subtitlesoctopus: .git/HEAD build/license_extract.sh
+	@mkdir -p dist/license
+	build/license_extract.sh build/license_defaults subtitlesoctopus src > dist/license/subtitlesoctopus
+
+dist/license/all: dist/license/subtitlesoctopus $(addprefix dist/license/, $(LIB_LICENSES)) build/license_fullnotice build/license_lint.awk
+	@echo "# The following lists all copyright notices and licenses for the" >  dist/license/all
+	@echo "# work contained in JavascriptSubtitlesOctopus per project."      >> dist/license/all
+	@echo "" >> dist/license/all
+
+	@echo "Concatenate extracted license info..."
+	@$(foreach LIB_PROJ, subtitlesoctopus $(LIB_LICENSES), \
+		echo "# Project: $(LIB_PROJ)"  >> dist/license/all && \
+		cat  dist/license/$(LIB_PROJ)  >> dist/license/all && \
+	) :
+
+	mv dist/license/all dist/license/all.tmp
+	build/license_lint.awk dist/license/all.tmp build/license_fullnotice
+	cat dist/license/all.tmp build/license_fullnotice > dist/license/all
+
+dist/js/COPYRIGHT: dist/license/all
+	cp "$<" "$@"