ci: use ccache (#78)

.github/patches/5.15/0001-Makefile-Use-CCACHE-for-faster-compilation.patch

@@ -0,0 +1,48 @@
+From f1e398602b989ac197cdd0fda4a7c4c323b03eb9 Mon Sep 17 00:00:00 2001
+From: DozNaka <dozdguide@gmail.com>
+Date: Mon, 11 Apr 2022 20:43:45 -0400
+Subject: [PATCH] Makefile: Use CCACHE for faster compilation
+
+---
+ Makefile | 20 ++++++++++----------
+ 1 file changed, 10 insertions(+), 10 deletions(-)
+
+diff --git a/Makefile b/Makefile
+index e8b8d5894..51e8aac6e 100644
+--- a/Makefile
++++ b/Makefile
+@@ -442,21 +442,21 @@ KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
+ # Make variables (CC, etc...)
+ CPP		= $(CC) -E
+ ifneq ($(LLVM),)
+-CC		= clang
+-LD		= ld.lld
+-AR		= llvm-ar
++CC		= $(CCACHE) clang
++LD		= $(CCACHE) ld.lld
++AR		= $(CCACHE) llvm-ar
+ NM		= llvm-nm
+-OBJCOPY		= llvm-objcopy
+-OBJDUMP		= llvm-objdump
++OBJCOPY		= $(CCACHE) llvm-objcopy
++OBJDUMP		= $(CCACHE) llvm-objdump
+ READELF		= llvm-readelf
+ STRIP		= llvm-strip
+ else
+-CC		= $(CROSS_COMPILE)gcc
+-LD		= $(CROSS_COMPILE)ld
+-AR		= $(CROSS_COMPILE)ar
++CC		= $(CCACHE) $(CROSS_COMPILE)gcc
++LD		= $(CCACHE) $(CROSS_COMPILE)ld
++AR		= $(CCACHE) $(CROSS_COMPILE)ar
+ NM		= $(CROSS_COMPILE)nm
+-OBJCOPY		= $(CROSS_COMPILE)objcopy
+-OBJDUMP		= $(CROSS_COMPILE)objdump
++OBJCOPY		= $(CCACHE) $(CROSS_COMPILE)objcopy
++OBJDUMP		= $(CCACHE) $(CROSS_COMPILE)objdump
+ READELF		= $(CROSS_COMPILE)readelf
+ STRIP		= $(CROSS_COMPILE)strip
+ endif
+-- 
+2.37.2
+