internal/cabi: support riscv64/riscv32 target-abi

internal/crosscompile/crosscompile.go

@@ -34,6 +34,7 @@ type Export struct {
 	ClangRoot    string   // Root directory of custom clang installation
 	ClangBinPath string   // Path to clang binary directory
 
+	LLVMTarget   string // LLVM Target
 	TargetABI    string // RISC-V Target ABI (e.g., "lp64", "lp64d")
 	BinaryFormat string // Binary format (e.g., "elf", "esp", "uf2")
 	FormatDetail string // For uf2, it's uf2FamilyID
@@ -454,6 +455,7 @@ func UseTarget(targetName string) (export Export, err error) {
 	export.GOOS = config.GOOS
 	export.GOARCH = config.GOARCH
 	export.ExtraFiles = config.ExtraFiles
+	export.LLVMTarget = config.LLVMTarget
 	export.TargetABI = config.TargetABI
 	export.BinaryFormat = config.BinaryFormat
 	export.FormatDetail = config.FormatDetail()