C tests should find clang binary using utility script

Author: xxuejie

tests/sphincsplus/Makefile

@@ -1,8 +1,8 @@
 cur_dir = $(dir $(abspath $(firstword $(MAKEFILE_LIST))))
-
-CLANG := clang-18
 TOP := $(cur_dir)/../..
 
+CLANG := $(shell $(TOP)/scripts/find_clang)
+
 PARAMS = sphincs-shake-256f
 THASH = robust
 

tests/sphincsplus/fuzzer/Makefile

@@ -2,7 +2,7 @@ cur_dir = $(dir $(abspath $(firstword $(MAKEFILE_LIST))))
 TOP := $(cur_dir)/../../..
 
 # Generate code, user performance analysis
-CC := clang-18
+CLANG := $(shell $(TOP)/scripts/find_clang)
 LLVM_PROFDATA := $(subst clang,llvm-profdata,$(CC))
 LLVM_COV := $(subst clang,llvm-cov,$(CC))
 

tests/sphincsplus/optimization/Makefile

@@ -1,7 +1,7 @@
 cur_dir = $(dir $(abspath $(firstword $(MAKEFILE_LIST))))
 TOP := $(cur_dir)/../../..
 
-CC := clang-18
+CLANG := $(shell $(TOP)/scripts/find_clang)
 
 PARAMS = sphincs-shake-128f
 THASH = simple