From bba3868b3b1dfd7741d33b119f73b5d342b9f1d5 Mon Sep 17 00:00:00 2001
From: pandaman <kointosudesuyo@infoseek.jp>
Date: Wed, 13 May 2026 23:00:35 +0900
Subject: [PATCH] fix: omit empty moreLeancArgs when leanc flags are unset
 (#13723)

This PR fixes toml_escape so it does not emit moreLeancArgs = [""] when
internal leanc flags are both empty (the combined placeholder was only
whitespace). This led GCC to see an extra empty argv entry and fail with
a confusing linker error.

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 src/CMakeLists.txt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b764dc260e..6199a89b8c 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1064,8 +1064,8 @@ configure_file(${LEAN_SOURCE_DIR}/stdlib.make.in ${CMAKE_BINARY_DIR}/stdlib.make
 
 # hacky
 function(toml_escape IN OUTVAR)
-  if(IN)
-    string(STRIP "${IN}" OUT)
+  string(STRIP "${IN}" OUT)
+  if(OUT)
     string(REPLACE " " "\", \"" OUT "${OUT}")
     set(${OUTVAR} "\"${OUT}\"" PARENT_SCOPE)
   endif()