rules.mk: set default host tools GCC optimization level to -O2

This patch can help save over 60% of package build time. -O2
optimization level is the default value before the commit
e8b470139c78 ("tools: add options to optimize host binaries").

Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/18812
Signed-off-by: Robert Marko <robimarko@gmail.com>

diff --git a/rules.mk b/rules.mk
index ccf97fe7b7bb9b5eefebd6b173ac1a7b6746f093..3971852f454a310fdea0d2b7ed042c1e386533f7 100644 (file)
--- a/rules.mk
+++ b/rules.mk
@@ -278,7 +278,7 @@ PKG_CONFIG:=$(STAGING_DIR_HOST)/bin/pkg-config
 
 export PKG_CONFIG
 
-HOST_FLAGS_OPT:=$(call qstrip,$(CONFIG_HOST_FLAGS_OPT))
+HOST_FLAGS_OPT:=$(if $(CONFIG_HOST_FLAGS_OPT),$(call qstrip,$(CONFIG_HOST_FLAGS_OPT)),"-O2")
 HOST_FLAGS_STRIP:=$(call qstrip,$(CONFIG_HOST_FLAGS_STRIP))
 HOST_EXTRA_CFLAGS:=$(call qstrip,$(CONFIG_HOST_EXTRA_CFLAGS))
 HOST_EXTRA_CXXFLAGS:=$(call qstrip,$(CONFIG_HOST_EXTRA_CXXFLAGS))