diff --git a/macosx-support-lib-patches/spandsp-configure-patch b/macosx-support-lib-patches/spandsp-configure-patch
new file mode 100644
index 0000000000..5a898f993e
--- /dev/null
+++ b/macosx-support-lib-patches/spandsp-configure-patch
@@ -0,0 +1,53 @@
+*** configure.dist	2014-06-04 07:28:14.000000000 -0700
+--- configure	2017-08-07 00:16:39.000000000 -0700
+***************
+*** 19658,19664 ****
+  
+  case "${ax_cv_c_compiler_vendor}" in
+  gnu)
+!     COMP_VENDOR_CFLAGS="-std=gnu99 -ffast-math -Wall -Wunused-variable -Wunused-but-set-variable -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes $COMP_VENDOR_CFLAGS"
+      if test "$enable_avx" = "yes" ; then
+          COMP_VENDOR_CFLAGS="-mavx $COMP_VENDOR_CFLAGS"
+      fi
+--- 19658,19664 ----
+  
+  case "${ax_cv_c_compiler_vendor}" in
+  gnu)
+!     COMP_VENDOR_CFLAGS="-std=gnu99 -ffast-math -Wall -Wunused-variable -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes $COMP_VENDOR_CFLAGS"
+      if test "$enable_avx" = "yes" ; then
+          COMP_VENDOR_CFLAGS="-mavx $COMP_VENDOR_CFLAGS"
+      fi
+***************
+*** 19733,19739 ****
+  
+      ;;
+  intel)
+!     COMP_VENDOR_CFLAGS="-std=c99 -D_POSIX_C_SOURCE=2 -D_GNU_SOURCE=1 -Wall -Wunused-variable -Wunused-but-set-variable -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes $COMP_VENDOR_CFLAGS"
+      if test "$enable_avx" = "yes" ; then
+          COMP_VENDOR_CFLAGS="-mavx $COMP_VENDOR_CFLAGS"
+      fi
+--- 19733,19739 ----
+  
+      ;;
+  intel)
+!     COMP_VENDOR_CFLAGS="-std=c99 -D_POSIX_C_SOURCE=2 -D_GNU_SOURCE=1 -Wall -Wunused-variable -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes $COMP_VENDOR_CFLAGS"
+      if test "$enable_avx" = "yes" ; then
+          COMP_VENDOR_CFLAGS="-mavx $COMP_VENDOR_CFLAGS"
+      fi
+***************
+*** 19767,19773 ****
+      COMP_VENDOR_LDFLAGS=
+      ;;
+  *)
+!     COMP_VENDOR_CFLAGS="-std=c99 -Wall -Wunused-variable -Wunused-but-set-variable -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes $COMP_VENDOR_CFLAGS"
+      COMP_VENDOR_LDFLAGS=
+      ;;
+  esac
+--- 19767,19773 ----
+      COMP_VENDOR_LDFLAGS=
+      ;;
+  *)
+!     COMP_VENDOR_CFLAGS="-std=c99 -Wall -Wunused-variable -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes $COMP_VENDOR_CFLAGS"
+      COMP_VENDOR_LDFLAGS=
+      ;;
+  esac
diff --git a/tools/macos-setup.sh b/tools/macos-setup.sh
index 8c9cb7d6ce..01334b1b00 100755
--- a/tools/macos-setup.sh
+++ b/tools/macos-setup.sh
@@ -1862,6 +1862,12 @@ install_spandsp() {
         $no_build && echo "Skipping installation" && return
         gzcat spandsp-$SPANDSP_VERSION.tar.gz | tar xf - || exit 1
         cd spandsp-$SPANDSP_VERSION
+        #
+        # Don't use -Wunused-but-set-variable, as it's not supported
+        # by all the gcc versions in the versions of Xcode that we
+        # support.
+        #
+        patch -p0 <../../macosx-support-lib-patches/spandsp-configure-patch || exit 1
         ./configure || exit 1
         make $MAKE_BUILD_OPTS || exit 1
         $DO_MAKE_INSTALL || exit 1