From af6c84b5238a7bfd20aeb2195af86c51cb2e73cf Mon Sep 17 00:00:00 2001
From: Sergei Zimmerman <sergei@zimmerman.foo>
Date: Sun, 20 Jul 2025 21:33:15 +0300
Subject: [PATCH] libexpr: Speed up builds by using precompiled headers

---
 src/libexpr/meson.build                | 1 +
 src/libexpr/pch/precompiled-headers.hh | 1 +
 2 files changed, 2 insertions(+)
 create mode 100644 src/libexpr/pch/precompiled-headers.hh

diff --git a/src/libexpr/meson.build b/src/libexpr/meson.build
index f5adafae0..fe795a607 100644
--- a/src/libexpr/meson.build
+++ b/src/libexpr/meson.build
@@ -178,6 +178,7 @@ this_library = library(
   link_args: linker_export_flags,
   prelink : true, # For C++ static initializers
   install : true,
+  cpp_pch : ['pch/precompiled-headers.hh']
 )
 
 install_headers(headers, subdir : 'nix/expr', preserve_path : true)
diff --git a/src/libexpr/pch/precompiled-headers.hh b/src/libexpr/pch/precompiled-headers.hh
new file mode 100644
index 000000000..1c9417b37
--- /dev/null
+++ b/src/libexpr/pch/precompiled-headers.hh
@@ -0,0 +1 @@
+#include "nix/expr/eval.hh"