lz4: Remove ancient test helpers

Building lz4 as root was causing `make clean` to fail with permission
errors.

We used to have to install lz4 from source back in Ubuntu 14.04, but
nowadays the installed lz4 is fine. Get rid of ancient helpers and
cruft!

.github/workflows/dev-short-tests.yml

@@ -170,7 +170,6 @@ jobs:
     - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # tag=v4.2.2
     - name: LZ4, thread pool, and libs build testslib wrapper test
       run: |
-        make lz4install
         make -C tests test-lz4
         make check < /dev/null | tee   # mess with lz4 console detection
         make clean

Makefile

@@ -351,7 +351,7 @@ apt-add-repo:
 	sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
 	sudo apt-get update -y -qq
 
-.PHONY: ppcinstall arminstall valgrindinstall libc6install gcc6install gcc7install gcc8install gpp6install clang38install lz4install
+.PHONY: ppcinstall arminstall valgrindinstall libc6install gcc6install gcc7install gcc8install gpp6install clang38install
 ppcinstall:
 	APT_PACKAGES="qemu-system-ppc qemu-user-static gcc-powerpc-linux-gnu" $(MAKE) apt-install
 
@@ -379,10 +379,6 @@ gpp6install: apt-add-repo
 clang38install:
 	APT_PACKAGES="clang-3.8" $(MAKE) apt-install
 
-# Ubuntu 14.04 ships a too-old lz4
-lz4install:
-	[ -e lz4 ] || git clone https://github.com/lz4/lz4 && sudo $(MAKE) -C lz4 install
-
 endif
 
 

tests/Makefile

@@ -447,9 +447,9 @@ test-decodecorpus-cli: decodecorpus
 test-pool: poolTests
 	$(QEMU_SYS) ./poolTests
 
-test-lz4: ZSTD = LD_LIBRARY_PATH=/usr/local/lib $(PRGDIR)/zstd
-test-lz4: ZSTD_LZ4 = LD_LIBRARY_PATH=/usr/local/lib ./lz4
-test-lz4: ZSTD_UNLZ4 = LD_LIBRARY_PATH=/usr/local/lib ./unlz4
+test-lz4: ZSTD = $(PRGDIR)/zstd
+test-lz4: ZSTD_LZ4 = ./lz4
+test-lz4: ZSTD_UNLZ4 = ./unlz4
 test-lz4: zstd decodecorpus datagen
 	[ -f lz4 ] || ln -s $(PRGDIR)/zstd lz4
 	[ -f unlz4 ] || ln -s $(PRGDIR)/zstd unlz4