diff --git a/devel/llvm/PRE_BUILD b/devel/llvm/PRE_BUILD
index b424472..bcde14f 100755
--- a/devel/llvm/PRE_BUILD
+++ b/devel/llvm/PRE_BUILD
@@ -28,10 +28,17 @@ if [[ "$LLVM_WITH_POLLY" == y ]]; then
fi &&
+
# small cmake related fix for libffi
if spell_ok libffi;then
FFI=`pkg-config --cflags-only-I libffi` &&
@@ -41,4 +48,9 @@ if spell_ok libffi;then
fi &&
# do not build all backends
-sed -i "/^set.*all\"$/s/all//" CMakeLists.txt
+sed -i "/^set.*all\"$/s/all//" CMakeLists.txt &&
+
+# Bugfix for llvm 12.0.0, cf. https://groups.google.com/g/llvm-dev/c/gIY5COm6V5E
+# This will probably be fixed in llvm 12.0.1.
+cd "$SOURCE_DIRECTORY/tools" &&
+patch -p1 <
"$SPELL_DIRECTORY/0001-Include-libunwind-from-source-directory.patch"
[SM-Commit] GIT changes to master grimoire by Florian Franzmann (83295fe5fa95f55198b32a4a2a23d342e4104b58),
Florian Franzmann, 05/02/2021