internal/rosa/package: migrate llvm patches

LLVM itself is unlikely to ever be migrated due to complexity of the bootstrap, so migrate patches instead.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/llvm.go

@@ -1,9 +1,11 @@
 package rosa
 
 import (
+	"io/fs"
 	"regexp"
 	"slices"
 	"strings"
+	"unsafe"
 
 	"hakurei.app/internal/pkg"
 )
@@ -48,6 +50,24 @@ func litArgs(verbose bool, skipChecks ...string) string {
 }
 
 func init() {
+	var llvmPatches []KV
+	for _, name := range [...]string{
+		"increase-stack-size-unconditional",
+		"add-rosa-vendor",
+		"xfail-broken-tests",
+		"path-system-include",
+		"path-system-libraries",
+	} {
+		p, err := fs.ReadFile(nativeB, "package/llvm/"+name+".patch")
+		if err != nil {
+			panic(err)
+		}
+		llvmPatches = append(llvmPatches, KV{
+			name,
+			unsafe.String(unsafe.SliceData(p), len(p)),
+		})
+	}
+
 	native.MustRegister("early-compiler-rt", func(t Toolchain) (*Metadata, pkg.Artifact) {
 		meta := Metadata{
 			Name:        "early-compiler-rt",