diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2af38729071b..6aa7bf15479d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,7 +52,8 @@ if(NOT CMAKE_SYSTEM_NAME MATCHES "Emscripten")
       # Use same platform flags as for Lean executables, in particular from `prepare-llvm-linux.sh`,
       # but not Lean-specific `LEAN_EXTRA_CXX_FLAGS` such as fsanitize.
       set(CADICAL_CXXFLAGS "${CMAKE_CXX_FLAGS}")
-      set(CADICAL_LDFLAGS "-Wl,-rpath=\\$$ORIGIN/../lib")
+      string(REPLACE "ROOT" "${CMAKE_BINARY_DIR}/stage1" CADICAL_INTERNAL_LINKER_FLAGS "${LEANC_INTERNAL_LINKER_FLAGS}")
+      set(CADICAL_LDFLAGS "${CADICAL_INTERNAL_LINKER_FLAGS} -Wl,-rpath=\\$$ORIGIN/../lib")
     endif()
     find_program(CCACHE ccache)
     if(CCACHE)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 372be2b36bc0..b764dc260eaa 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1075,6 +1075,7 @@ string(REPLACE "ROOT" "${CMAKE_BINARY_DIR}" LEANC_INTERNAL_FLAGS "${LEANC_INTERN
 string(REPLACE "ROOT" "${CMAKE_BINARY_DIR}" LEANC_INTERNAL_LINKER_FLAGS "${LEANC_INTERNAL_LINKER_FLAGS}")
 
 toml_escape("${LEAN_EXTRA_OPTS}" LEAN_EXTRA_OPTS_TOML)
+toml_escape("${LEANC_INTERNAL_FLAGS} ${LEANC_INTERNAL_LINKER_FLAGS}" LEAN_MORE_LEANC_ARGS_TOML)
 
 if(CMAKE_BUILD_TYPE MATCHES "Debug|Release|RelWithDebInfo|MinSizeRel")
   set(CMAKE_BUILD_TYPE_TOML "${CMAKE_BUILD_TYPE}")
diff --git a/src/lakefile.toml.in b/src/lakefile.toml.in
index c0faf4fa46d2..21e59a9e4a14 100644
--- a/src/lakefile.toml.in
+++ b/src/lakefile.toml.in
@@ -46,6 +46,8 @@ moreLeanArgs = [${LEAN_EXTRA_OPTS_TOML}]
 # Uncomment to limit number of reported errors further in case of overwhelming cmdline output
 #weakLeanArgs = ["-DmaxErrors=1"]
 
+moreLeancArgs = [${LEAN_MORE_LEANC_ARGS_TOML}]
+
 ${LEAN_EXTRA_LAKEFILE_TOML}
 
 [[lean_lib]]
diff --git a/tests/bench_build.sh b/tests/bench_build.sh
index c91fb109acd8..749cc9682ceb 100755
--- a/tests/bench_build.sh
+++ b/tests/bench_build.sh
@@ -1,10 +1,28 @@
-#!/usr/bin/env bash
+#!/usr/bin/env nix
+#! nix develop ..#oldGlibc --command /usr/bin/env bash
 
 # This script must be called from the repo root.
 # The radar environment variables must be provided.
 # See also the https://github.com/leanprover/radar readme.
 
-cmake --preset release -DWFAIL=OFF
+LLVM_RELEASE=19.1.2
+LLVM_TARBALL="$RADAR_CACHE/llvm/$LLVM_RELEASE.tar.zst"
+
+if [ ! -f "$LLVM_TARBALL" ]; then
+    mkdir -p "$RADAR_CACHE/llvm"
+    curl --location -o "$LLVM_TARBALL" "https://github.com/leanprover/lean-llvm/releases/download/$LLVM_RELEASE/lean-llvm-x86_64-linux-gnu.tar.zst"
+fi
+
+mkdir -p build/release
+cd build/release
+eval cmake ../.. \
+    --preset release $(../../script/prepare-llvm-linux.sh $LLVM_TARBALL) \
+    -DWFAIL=OFF
+rm -rf stage2
+cp -r stage1 stage2
+rm -rf stage3
+cp -r stage1 stage3
+cd ../..
 make -C build/release -j"$(nproc)" bench-part1
 mv tests/part1.measurements.jsonl "$RADAR_OUT"
 
diff --git a/tests/bench_other.sh b/tests/bench_other.sh
index 18d23d0019a2..98bae3ff685a 100755
--- a/tests/bench_other.sh
+++ b/tests/bench_other.sh
@@ -1,9 +1,27 @@
-#!/usr/bin/env bash
+#!/usr/bin/env nix
+#! nix develop ..#oldGlibc --command /usr/bin/env bash
 
 # This script must be called from the repo root.
 # The radar environment variables must be provided.
 # See also the https://github.com/leanprover/radar readme.
 
-cmake --preset release -DWFAIL=OFF
+LLVM_RELEASE=19.1.2
+LLVM_TARBALL="$RADAR_CACHE/llvm/$LLVM_RELEASE.tar.zst"
+
+if [ ! -f "$LLVM_TARBALL" ]; then
+    mkdir -p "$RADAR_CACHE/llvm"
+    curl --location -o "$LLVM_TARBALL" "https://github.com/leanprover/lean-llvm/releases/download/$LLVM_RELEASE/lean-llvm-x86_64-linux-gnu.tar.zst"
+fi
+
+mkdir -p build/release
+cd build/release
+eval cmake ../.. \
+    --preset release $(../../script/prepare-llvm-linux.sh $LLVM_TARBALL) \
+    -DWFAIL=OFF
+rm -rf stage2
+cp -r stage1 stage2
+rm -rf stage3
+cp -r stage1 stage3
+cd ../..
 make -C build/release -j"$(nproc)" bench-part2
 mv tests/part2.measurements.jsonl "$RADAR_OUT"