Try build bpftools with clang

SPECS/kernel-6.1.spec

@@ -1295,11 +1295,8 @@ popd > /dev/null
 %endif
 
 %if %{with_bpftool}
-export CC=gcc
-export CXX=g++
-
 %global bpftool_make \
-	%{__make} -s CC=gcc CXX=g++ EXTRA_CFLAGS="${RPM_OPT_FLAGS}" EXTRA_LDFLAGS="%{__global_ldflags}" DESTDIR=$RPM_BUILD_ROOT VMLINUX_H="${RPM_VMLINUX_H}"
+	%{__make} HOSTCC=clang CC=clang -s EXTRA_CFLAGS="${RPM_OPT_FLAGS}" EXTRA_LDFLAGS="%{__global_ldflags}" DESTDIR=$RPM_BUILD_ROOT VMLINUX_H="${RPM_VMLINUX_H}"
 
 pushd tools/bpf/bpftool > /dev/null
 %{bpftool_make}