lz4: Fix parallel build, again

The 'test' target in the examples directory tries to execute the lz4
binary. This may fail if the build for this binary is still running.
Partly backport an upstream commit that moves the test execution of
examples to the 'make test' target.

See: https://trac.macports.org/ticket/55896

archivers/lz4/files/parallel.patch

@@ -2,8 +2,9 @@ Fix parallel build
 https://github.com/lz4/lz4/issues/481
 https://github.com/lz4/lz4/commit/886a4858451800f6ebd621a2816a4698486d7ff1
 https://github.com/lz4/lz4/commit/6d4e60e365d1353c9dac46f5bcfa48edfd9ab623
---- Makefile.orig	2018-01-14 02:21:43.000000000 -0600
-+++ Makefile	2018-03-09 12:05:15.000000000 -0600
+https://github.com/lz4/lz4/commit/87fb7a1d031a7e6df72d5ca50ab543a57ddca21f#diff-b67911656ef5d18c4ae36cb6741b7965
+--- Makefile.orig	2018-03-20 23:47:06.000000000 +0100
++++ Makefile	2018-03-20 23:48:01.000000000 +0100
 @@ -58,6 +58,7 @@
  allmost: lib lz4 examples
 
@@ -12,12 +13,22 @@ https://github.com/lz4/lz4/commit/6d4e60e365d1353c9dac46f5bcfa48edfd9ab623
  lib lib-release liblz4.a:
  	@$(MAKE) -C $(LZ4DIR) $@
 
-@@ -69,7 +70,7 @@
+@@ -69,8 +70,8 @@
  	@cp $(PRGDIR)/lz4$(EXT) .
 
  .PHONY: examples
 -examples: lib lz4
+-	$(MAKE) -C $(EXDIR) test
 +examples: liblz4.a
- 	$(MAKE) -C $(EXDIR) test
++	$(MAKE) -C $(EXDIR) all
 
  .PHONY: manuals
+ manuals:
+@@ -125,6 +126,7 @@
+ .PHONY: test
+ test:
+ 	$(MAKE) -C $(TESTDIR) $@
++	$(MAKE) -C $(EXDIR) $@
+
+ clangtest: clean
+ 	clang -v