diffutils: don't build with __FORTIFY_SOURCE=2 if debug

packages/diffutils/build.sh

@@ -7,3 +7,11 @@ TERMUX_PKG_SHA256=b3a7a6221c3dc916085f0d205abf6b8e1ba443d4dd965118da364a1dc1cb3a
 TERMUX_PKG_SRCURL=https://mirrors.kernel.org/gnu/diffutils/diffutils-${TERMUX_PKG_VERSION}.tar.xz
 TERMUX_PKG_DEPENDS="libiconv"
 TERMUX_PKG_EXTRA_CONFIGURE_ARGS="ac_cv_path_PR_PROGRAM=${TERMUX_PREFIX}/bin/pr"
+
+termux_step_pre_configure() {
+	if [ "$TERMUX_DEBUG" == "true" ]; then
+		# When doing debug build, -D_FORTIFY_SOURCE=2 gives an
+		# error: use of undeclared identifier '__USE_FORTIFY_LEVEL'
+		export CFLAGS=${CFLAGS/-D_FORTIFY_SOURCE=2/}
+	fi
+}