Fix zstd/zdict include path for java static build

Summary:
With the ZSTD dictionary generator support added in #3057
`PORTABLE=1 ROCKSDB_NO_FBCODE=1 make rocksdbjavastatic` fails as it can't find zdict.h. Specifically due to:
e3a06f12d2/util/compression.h (L39)
In java static builds zstd code gets directly downloaded from https://github.com/facebook/zstd , and in there zdict.h is under dictBuilder directory. So, I modified libzstd.a target to use `make install` to collect all the header files into a single location and used that as the zstd's include path.
Closes https://github.com/facebook/rocksdb/pull/3260

Differential Revision: D6669850

Pulled By: sagar0

fbshipit-source-id: f8a7562a670e5aed4c4fb6034a921697590d7285

Makefile

@@ -1651,7 +1651,7 @@ libzstd.a:
 		exit 1; \
 	fi
 	tar xvzf zstd-$(ZSTD_VER).tar.gz
-	cd zstd-$(ZSTD_VER)/lib && make CFLAGS='-fPIC -O2 ${EXTRA_CFLAGS}' all
+	cd zstd-$(ZSTD_VER)/lib && DESTDIR=. PREFIX= make CFLAGS='-fPIC -O2 ${EXTRA_CFLAGS}' install
 	cp zstd-$(ZSTD_VER)/lib/libzstd.a .
 
 # A version of each $(LIBOBJECTS) compiled with -fPIC and a fixed set of static compression libraries
@@ -1664,7 +1664,7 @@ JAVA_COMPRESSIONS = libz.a libbz2.a libsnappy.a liblz4.a libzstd.a
 endif
 
 JAVA_STATIC_FLAGS = -DZLIB -DBZIP2 -DSNAPPY -DLZ4 -DZSTD
-JAVA_STATIC_INCLUDES = -I./zlib-$(ZLIB_VER) -I./bzip2-$(BZIP2_VER) -I./snappy-$(SNAPPY_VER) -I./lz4-$(LZ4_VER)/lib -I./zstd-$(ZSTD_VER)/lib
+JAVA_STATIC_INCLUDES = -I./zlib-$(ZLIB_VER) -I./bzip2-$(BZIP2_VER) -I./snappy-$(SNAPPY_VER) -I./lz4-$(LZ4_VER)/lib -I./zstd-$(ZSTD_VER)/lib/include
 
 ifeq ($(HAVE_POWER8),1)
 JAVA_STATIC_C_LIBOBJECTS = $(patsubst %.c.o,jls/%.c.o,$(LIB_SOURCES_C:.c=.o))