all: use LLVM=1 for building Linux with clang

This is the standard way now.

Since our configuration permits multiple parameter value combinations,
explicitly check for the compiler and linker that were to be passed via
CC and LD, and replace that with LLVM=1 if they were clang and ld.lld
correspondingly.

Update syz-kconf to rely on pkg/build's exported functionality for
generating Linux kernel build arguments.

1 files changed, 8 insertions, 3 deletions

diff --git a/sys/targets/targets.go b/sys/targets/targets.go
index 2cf001473..50f5c5121 100644
--- a/sys/targets/targets.go
+++ b/sys/targets/targets.go
@@ -881,6 +881,11 @@ func (target *Target) Timeouts(slowdown int) Timeouts {
 	return timeouts
 }
 
+const (
+	DefaultLLVMCompiler = "clang"
+	DefaultLLVMLinker   = "ld.lld"
+)
+
 func (target *Target) setCompiler(clang bool) {
 	// setCompiler may be called effectively twice for target.other,
 	// so first we remove flags the previous call may have added.
@@ -895,9 +900,9 @@ func (target *Target) setCompiler(clang bool) {
 	}
 	target.CFlags = target.CFlags[:pos]
 	if clang {
-		target.CCompiler = "clang"
-		target.KernelCompiler = "clang"
-		target.KernelLinker = "ld.lld"
+		target.CCompiler = DefaultLLVMCompiler
+		target.KernelCompiler = DefaultLLVMCompiler
+		target.KernelLinker = DefaultLLVMLinker
 		if target.Triple != "" {
 			target.CFlags = append(target.CFlags, "--target="+target.Triple)
 		}