[UNIKRAFT PATCH 2/3] support/build: Add build functions for clang and gcc check

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

We add have_gcc and have_clang. We modify gcc_version_ge to
use have_gcc.

Signed-off-by: Alice Suiu <alicesuiu17@xxxxxxxxx>
Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@xxxxxx>
---
 support/build/Makefile.rules | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/support/build/Makefile.rules b/support/build/Makefile.rules
index 9a5963fd..ecd409f0 100644
--- a/support/build/Makefile.rules
+++ b/support/build/Makefile.rules
@@ -29,10 +29,20 @@ lc = $(subst A,a,$(subst B,b,$(subst C,c,$(subst 
D,d,$(subst E,e,$(subst F,f,$(s
 # upper case
 uc = $(subst a,A,$(subst b,B,$(subst c,C,$(subst d,D,$(subst e,E,$(subst 
f,F,$(subst g,G,$(subst h,H,$(subst i,I,$(subst j,J,$(subst k,K,$(subst 
l,L,$(subst m,M,$(subst n,N,$(subst o,O,$(subst p,P,$(subst q,Q,$(subst 
r,R,$(subst s,S,$(subst t,T,$(subst u,U,$(subst v,V,$(subst w,W,$(subst 
x,X,$(subst y,Y,$(subst z,Z,$(1)))))))))))))))))))))))))))
 
+# test if GCC is set as a compiler
+define have_gcc =
+$(shell if [ $(CC) = gcc ] ; then echo y ; else echo n ; fi)
+endef
+
+# test if CLANG is set as a compiler
+define have_clang =
+$(shell if [ $(CC) == clang ] ; then echo y ; else echo n ; fi)
+endef
+
 # test whether GCC version is greater than or equal to the minimum requirement
 # gcc_version_ge $gcc_major,$gcc_minor
 define gcc_version_ge =
-$(shell if [ $(CC_VER_MAJOR) -gt $(1) ] || ([ $(CC_VER_MAJOR) -eq $(1) ] && [ 
$(CC_VER_MINOR) -ge $(2) ]) ; then echo y ; fi)
+$(shell if [ $(call have_gcc) = y ] ; then if [ $(CC_VER_MAJOR) -gt $(1) ] || 
([ $(CC_VER_MAJOR) -eq $(1) ] && [ $(CC_VER_MINOR) -ge $(2) ]) ; then echo y ; 
fi ; else echo n ; fi)
 endef
 
 # print error and stop build when GCC version doesn't meet the minimum 
requirement
-- 
2.27.0