internal/rosa/llvm: patch source tree

A few patches are required for disabling broken tests and changing default search paths.

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

internal/rosa/llvm.go

@@ -27,6 +27,9 @@ type llvmAttr struct {
 	script string
 	// Passed through to CMakeAttr.Prefix.
 	prefix *check.Absolute
+
+	// Patch name and body pairs.
+	patches [][2]string
 }
 
 const (
@@ -172,12 +175,32 @@ cp -r /system/include /usr/include && rm -rf /system/include
 		)
 	}
 
-	return t.NewViaCMake("llvm", version, variant, pkg.NewHTTPGetTar(
+	source := pkg.NewHTTPGetTar(
 		nil, "https://github.com/llvm/llvm-project/archive/refs/tags/"+
 			"llvmorg-"+version+".tar.gz",
 		mustDecode(checksum),
 		pkg.TarGzip,
-	), &CMakeAttr{
+	)
+
+	patches := make([]pkg.ExecPath, len(attr.patches)+1)
+	for i, p := range attr.patches {
+		patches[i+1] = pkg.Path(
+			AbsUsrSrc.Append("llvm-patches", p[0]+".patch"), false,
+			pkg.NewFile(p[0], []byte(p[1])),
+		)
+	}
+	patches[0] = pkg.Path(AbsUsrSrc.Append("llvmorg"), false, source)
+	if len(patches) > 1 {
+		source = t.New(
+			"llvmorg-patched", nil, nil, nil, `
+cp -r /usr/src/llvmorg/. /work/.
+chmod -R +w /work && cd /work
+cat /usr/src/llvm-patches/* | patch -p 1
+`, patches...,
+		)
+	}
+
+	return t.NewViaCMake("llvm", version, variant, source, &CMakeAttr{
 		Cache:  slices.Concat(cache, attr.cmake),
 		Append: cmakeAppend,
 		Extra:  slices.Concat(attr.extra, extra),