pkg/build: move kernel release overrides to make args

When set as env variables, these don't seem to have any effect, but
start to work as indended when passed as explicit make arguments.

Author: a-nogikh

pkg/build/linux.go

@@ -175,9 +175,6 @@ func runMake(params Params, extraArgs ...string) error {
 		"KBUILD_BUILD_TIMESTAMP=now",
 		"KBUILD_BUILD_USER=syzkaller",
 		"KBUILD_BUILD_HOST=syzkaller",
-		"KERNELVERSION=syzkaller",
-		"KERNELRELEASE=syzkaller",
-		"LOCALVERSION=-syzkaller",
 	)
 	output, err := osutil.Run(time.Hour, cmd)
 	params.Tracer.Log("Build log:\n%s", output)
@@ -186,6 +183,11 @@ func runMake(params Params, extraArgs ...string) error {
 
 func LinuxMakeArgs(target *targets.Target, compiler, linker, ccache, buildDir string, jobs int) []string {
 	args := []string{
+		// Make still overrides these if they are passed as env variables.
+		// Let's pass them directly as make arguments.
+		"KERNELVERSION=syzkaller",
+		"KERNELRELEASE=syzkaller",
+		"LOCALVERSION=-syzkaller",
 		"-j", fmt.Sprint(jobs),
 		"ARCH=" + target.KernelArch,
 	}