python: add back -O3 to CFLAGS

packages/python/build.sh

@@ -44,6 +44,9 @@ lib/python${_MAJOR_VERSION}/*/tests
 "
 
 termux_step_pre_configure() {
+	# -O3 gains some additional performance on at least aarch64.
+	CFLAGS="${CFLAGS/-Oz/-O3}"
+
 	# Needed when building with clang, as setup.py only probes
 	# gcc for include paths when finding headers for determining
 	# if extension modules should be built (specifically, the