[UNIKRAFT PATCH v4 1/3] build: Option to configure the compiler

[Vlad-Andrei Badoiu <vlad_andrei.badoiu@xxxxxx>]

By default, the compiler is GCC. Use COMPILER to set the compiler. For
example, COMPILER=clang.

Signed-off-by: Alice Suiu <alicesuiu17@xxxxxxxxx>
Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@xxxxxx>
Reviewed-by: Razvan Deaconescu <razvan.deaconescu@xxxxxxxxx>
---
 Makefile | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 8e14817..c22dbad 100644
--- a/Makefile
+++ b/Makefile
@@ -513,6 +513,7 @@ ifeq ($(sub_make_exec), 1)
 ifeq ($(UK_HAVE_DOT_CONFIG),y)
 # Hide troublesome environment variables from sub processes
 unexport CONFIG_CROSS_COMPILE
+unexport CONFIG_COMPILER
 #unexport CC
 #unexport LD
 #unexport AR
@@ -545,11 +546,18 @@ ifneq ("$(origin CROSS_COMPILE)","undefined")
 CONFIG_CROSS_COMPILE := $(CROSS_COMPILE:"%"=%)
 endif
 
+ifneq ("$(origin COMPILER)","undefined")
+       CONFIG_COMPILER := $(COMPILER:"%"=%)
+else
+       CONFIG_COMPILER := gcc
+endif
+
+
 $(eval $(call verbose_include,$(CONFIG_UK_BASE)/arch/$(UK_FAMILY)/Compiler.uk))
 
 # Make variables (CC, etc...)
-LD             := $(CONFIG_CROSS_COMPILE)gcc
-CC             := $(CONFIG_CROSS_COMPILE)gcc
+LD             := $(CONFIG_CROSS_COMPILE)$(CONFIG_COMPILER)
+CC             := $(CONFIG_CROSS_COMPILE)$(CONFIG_COMPILER)
 CPP            := $(CC)
 CXX            := $(CPP)
 GOC            := $(CONFIG_CROSS_COMPILE)gccgo-7
-- 
2.27.0