[openwrt/openwrt] ccache: Speed up building.

[LEDE Commits]

blogic pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/1f11912138ce8a77cc0e2faa26942133d393b010

commit 1f11912138ce8a77cc0e2faa26942133d393b010
Author: Markus Gothe <markus.gothe at genexis.eu>
AuthorDate: Wed Jan 12 17:13:43 2022 +0100

    ccache: Speed up building.
    
    - Disable compression for ccache's cached files.
    - Disable the hashing of the CWD inside debug information. This
      increases the cache hits drastically.
    
    Signed-off-by: Markus Gothe <markus.gothe at genexis.eu>
---
 rules.mk | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/rules.mk b/rules.mk
index 54df407fca..9db7c72fa4 100644
--- a/rules.mk
+++ b/rules.mk
@@ -342,6 +342,8 @@ ifneq ($(CONFIG_CCACHE),)
   TARGET_CXX:= ccache $(TARGET_CXX)
   HOSTCC:= ccache $(HOSTCC)
   HOSTCXX:= ccache $(HOSTCXX)
+  export CCACHE_NOHASHDIR:=true
+  export CCACHE_NOCOMPRESS:=true
   export CCACHE_BASEDIR:=$(TOPDIR)
   export CCACHE_DIR:=$(if $(call qstrip,$(CONFIG_CCACHE_DIR)),$(call qstrip,$(CONFIG_CCACHE_DIR)),$(TOPDIR)/.ccache)
   export CCACHE_COMPILERCHECK:=%compiler% -dumpmachine; %compiler% -dumpversion