diff --git a/src/Makefile.am b/src/Makefile.am
index d6ed7eb41..a3332578f 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -594,7 +594,7 @@ libzcash_a_CPPFLAGS = -DMULTICORE -fopenmp -fPIC -DBOOST_SPIRIT_THREADSAFE -DHAV
 #libzcash_a_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 #libzcash_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) -DMONTGOMERY_OUTPUT
 
-libzcash_a_CXXFLAGS = $(SAN_CXXFLAGS) $(HARDENED_CXXFLAGS) -fwrapv -fno-strict-aliasing
+libzcash_a_CXXFLAGS = $(SAN_CXXFLAGS) $(HARDENED_CXXFLAGS) -fwrapv -fno-strict-aliasing -std=gnu17
 libzcash_a_LDFLAGS = $(SAN_LDFLAGS) $(HARDENED_LDFLAGS)
 libzcash_a_CPPFLAGS += -DMONTGOMERY_OUTPUT
 
@@ -636,7 +636,7 @@ libhush_a_SOURCES = \
 
 libhush_a_CPPFLAGS = -DMULTICORE -fopenmp -fPIC -DBINARY_OUTPUT -DCURVE_ALT_BN128 -DBOOST_SPIRIT_THREADSAFE -DHAVE_BUILD_INFO -D__STDC_FORMAT_MACROS $(HARDENED_CPPFLAGS) -pipe -O1 -g  -Wstack-protector -fstack-protector-all -fPIE -fvisibility=hidden -DSTATIC $(BITCOIN_INCLUDES)
 
-libhush_a_CXXFLAGS = $(HARDENED_CXXFLAGS) -fwrapv -fno-strict-aliasing
+libhush_a_CXXFLAGS = $(HARDENED_CXXFLAGS) -fwrapv -fno-strict-aliasing -std=gnu17
 
 libhush_a_LDFLAGS = $(HARDENED_LDFLAGS)
 
diff --git a/util/build.sh b/util/build.sh
index b362f2d11..da5622706 100755
--- a/util/build.sh
+++ b/util/build.sh
@@ -137,7 +137,7 @@ CONFIG_SITE="$PWD/depends/$HOST/share/config.site" ./configure "$HARDENING_ARG"
 WD=$PWD
 cd src/cc
 echo $PWD
-CC=${CC:-gcc} ./makecustom
+CFLAGS=-std=gnu17 CC=${CC:-gcc} ./makecustom
 cd $WD
 
 # Build RandomX
@@ -154,4 +154,5 @@ fi
 
 cd $WD
 
+CXXFLAGS+=-std=gnu17
 time "$MAKE" "$@" V=1