gentoo-overlay/dev-libs/leveldb/files/leveldb-1.20-memenv-so.patch

# Create libmemenv.so and don't compile programs by default
# Add a static_programs target to compile test programs
--- a/Makefile	2018-06-03 16:52:28.839614213 +0200
+++ b/Makefile	2018-06-03 16:52:18.209544310 +0200
@@ -128,15 +128,27 @@
 	ln -fs $(SHARED_LIB3) $(SHARED_OUTDIR)/$(SHARED_LIB1)
 $(SHARED_OUTDIR)/$(SHARED_LIB2): $(SHARED_OUTDIR)/$(SHARED_LIB3)
 	ln -fs $(SHARED_LIB3) $(SHARED_OUTDIR)/$(SHARED_LIB2)
+SHARED_MEMENV_LIB1 = libmemenv.$(PLATFORM_SHARED_EXT)
+SHARED_MEMENV_LIB2 = $(SHARED_MEMENV_LIB1).$(SHARED_VERSION_MAJOR)
+SHARED_MEMENV_LIB3 = $(SHARED_MEMENV_LIB1).$(SHARED_VERSION_MAJOR).$(SHARED_VERSION_MINOR)
+SHARED_MEMENV_LIBS = $(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB1) $(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB2) $(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB3)
+$(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB1): $(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB3)
+	ln -fs $(SHARED_MEMENV_LIB3) $(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB1)
+$(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB2): $(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB3)
+	ln -fs $(SHARED_MEMENV_LIB3) $(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB2)
 SHARED_MEMENVLIB = $(SHARED_OUTDIR)/libmemenv.a
 endif
 
 $(SHARED_OUTDIR)/$(SHARED_LIB3): $(SHARED_LIBOBJECTS)
 	$(CXX) $(LDFLAGS) $(PLATFORM_SHARED_LDFLAGS)$(SHARED_LIB2) $(SHARED_LIBOBJECTS) -o $(SHARED_OUTDIR)/$(SHARED_LIB3) $(LIBS)
+$(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB3): $(SHARED_MEMENVOBJECTS)
+	$(CXX) $(LDFLAGS) $(PLATFORM_SHARED_LDFLAGS)$(SHARED_MEMENV_LIB2) $(SHARED_MEMENVOBJECTS) -o $(SHARED_OUTDIR)/$(SHARED_MEMENV_LIB3) $(LIBS)
 
 endif  # PLATFORM_SHARED_EXT
 
-all: $(SHARED_LIBS) $(SHARED_PROGRAMS) $(STATIC_OUTDIR)/libleveldb.a $(STATIC_OUTDIR)/libmemenv.a $(STATIC_PROGRAMS)
+all: $(SHARED_LIBS) $(SHARED_MEMENV_LIBS)
+
+static_programs: $(STATIC_PROGRAMS)
 
 check: $(STATIC_PROGRAMS)
 	for t in $(notdir $(TESTS)); do echo "***** Running $$t"; $(STATIC_OUTDIR)/$$t || exit 1; done