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/package/llvm/increase-stack-size-unconditional.patch

@@ -0,0 +1,13 @@
+diff --git a/llvm/lib/Support/Threading.cpp b/llvm/lib/Support/Threading.cpp
+index 9da357a7ebb9..b2931510c1ae 100644
+--- a/llvm/lib/Support/Threading.cpp
++++ b/llvm/lib/Support/Threading.cpp
+@@ -80,7 +80,7 @@ unsigned llvm::ThreadPoolStrategy::compute_thread_count() const {
+ // keyword.
+ #include "llvm/Support/thread.h"
+ 
+-#if defined(__APPLE__)
++#if defined(__APPLE__) || 1
+   // Darwin's default stack size for threads except the main one is only 512KB,
+   // which is not enough for some/many normal LLVM compilations. This implements
+   // the same interface as std::thread but requests the same stack size as the