build: Split hardening/fPIE options out

This allows for fPIE to be used selectively.

Zcash: Second half of upstream commit 17c4d9d
First half was pulled in as c459de2

src/Makefile.bench.include

@@ -16,7 +16,8 @@ bench_bench_bitcoin_SOURCES = \
   bench/perf.h \
   bench/prevector_destructor.cpp
 
-bench_bench_bitcoin_CPPFLAGS = $(BITCOIN_INCLUDES) $(EVENT_CLFAGS) $(EVENT_PTHREADS_CFLAGS) -I$(builddir)/bench/
+bench_bench_bitcoin_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(EVENT_CLFAGS) $(EVENT_PTHREADS_CFLAGS) -I$(builddir)/bench/
+bench_bench_bitcoin_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 bench_bench_bitcoin_LDADD = \
   $(LIBBITCOIN_SERVER) \
   $(LIBBITCOIN_COMMON) \
@@ -38,7 +39,6 @@ endif
 bench_bench_bitcoin_LDADD += $(BOOST_LIBS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS) $(EVENT_PTHREADS_LIBS) $(EVENT_LIBS) $(LIBZCASH_LIBS)
 bench_bench_bitcoin_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 
-
 CLEAN_BITCOIN_BENCH = bench/*.gcda bench/*.gcno
 
 CLEANFILES += $(CLEAN_BITCOIN_BENCH)