Radix cross Linux 3pp sources

#
# Project Home:
# ============
# https://opencv.org
#
# GitHub:
# ======
# https://github.com/opencv/opencv
#
# Install instruction:
# ===================
# https://docs.opencv.org/2.4.13/doc/tutorials/introduction/linux_install/linux_install.html?highlight=install
#
# Clone:
# =====
# git clone https://github.com/opencv/opencv.git
#

url        = https://github.com/opencv

repo_name  = opencv

#
# List of tags to be extracted:
# ============================
#                                               hash | tag
#            ----------------------------------------+-----
revisions  = 59975db6a415c53b8e6f9bcb4e1ee5d3c4579ebf:2.4.13
revisions += 92387b1ef8fad15196dd5f7fb4931444a68bc93a:3.1.0
revisions += b0dc474160e389b9c9045da5db49d03ae17c6a6b:4.6.0
revisions += 725e440d278aca07d35a5e8963ef990572b07316:4.7.0

git_repo   = .git_clone

suffix     = tar.xz

versions   = $(foreach tag, $(revisions), $(shell echo $(tag) | cut -f 2 -d ':'))

tarballs   = $(addsuffix .$(suffix), $(addprefix $(repo_name)-, $(versions)))
sha1s      = $(addsuffix .sha1sum, $(tarballs))

TARGETS = repository_clean

all: $(TARGETS)

.PHONY: downloads_clean repository_clean

$(git_repo):
	@echo -e "\n======= Clone $(repo_name).git repository =======\n"
	@rm -rf $(repo_name)
	@git clone $(url)/$(repo_name).git $(repo_name)
	@touch $@

$(tarballs): $(git_repo)
	@for revision in $(revisions) ; do \
	  hash=`echo $$revision    | cut -f 1 -d ':'` ; \
	  version=`echo $$revision | cut -f 2 -d ':'` ; \
	  if [ ! -f $(repo_name)-$$version.$(suffix) ]; then \
	    echo -e "\n======= Creating '$(repo_name)-$$version.$(suffix)' snapshot =======" ; \
	    ( cd $(repo_name) && \
	      git archive --format=tar --prefix=$(repo_name)-$$version/ $$hash | \
	      xz >../$(repo_name)-$$version.$(suffix) ) ; \
	  fi ; \
	done

$(sha1s): %.$(suffix).sha1sum : %.$(suffix)
	@for tarball in $< ; do \
	  echo -e "\n======= Calculation the '$$tarball' sha1sum =======" ; \
	  sha1sum --binary $$tarball > $$tarball.sha1sum ; \
	done

repository_clean: $(sha1s)
	@echo -e "\n======= Remove cloned $(repo_name).git repository =======\n"
	@rm -rf $(git_repo) $(repo_name)

downloads_clean:
	@rm -rf $(tarballs) $(sha1s)
	@rm -rf $(git_repo) $(repo_name)