From 32779f7c87bfae82e8bdaf24ca93548bda5b96da Mon Sep 17 00:00:00 2001
From: =?utf8?q?St=C3=A9phane=20Glondu?= <glondu@debian.org>
Date: Sun, 1 Mar 2026 21:32:57 +0100
Subject: [PATCH] Stabilize compiler-libs ABI by not including config.cmx

---
 ...le-utils-config.-cmi-cmx-with-opaque.patch | 26 +++++++++++++++++++
 debian/patches/series                         |  1 +
 debian/rules                                  |  2 ++
 3 files changed, 29 insertions(+)
 create mode 100644 debian/patches/Compile-utils-config.-cmi-cmx-with-opaque.patch

diff --git a/debian/patches/Compile-utils-config.-cmi-cmx-with-opaque.patch b/debian/patches/Compile-utils-config.-cmi-cmx-with-opaque.patch
new file mode 100644
index 00000000..21758cb3
--- /dev/null
+++ b/debian/patches/Compile-utils-config.-cmi-cmx-with-opaque.patch
@@ -0,0 +1,26 @@
+From: =?utf-8?q?St=C3=A9phane_Glondu?= <glondu@debian.org>
+Date: Sun, 1 Mar 2026 21:32:31 +0100
+Subject: Compile utils/config.{cmi,cmx} with -opaque
+
+The goal is to stabilize compiler-libs ABI.
+---
+ Makefile | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/Makefile b/Makefile
+index 4ce5da6..c9d4300 100644
+--- a/Makefile
++++ b/Makefile
+@@ -2546,6 +2546,12 @@ endif
+ %.cmx: %.ml
+ 	$(V_OCAMLOPT)$(COMPILE_NATIVE_MODULE) -c $<
+ 
++utils/config.cmi: utils/config.mli
++	$(V_OCAMLC)$(CAMLC) $(OC_COMMON_COMPFLAGS) -I $(@D) $(INCLUDES) -opaque -c $<
++
++utils/config.cmx: utils/config.ml
++	$(V_OCAMLOPT)$(COMPILE_NATIVE_MODULE) -opaque -c $<
++
+ partialclean::
+ 	for d in utils parsing typing bytecomp asmcomp middle_end file_formats \
+            lambda middle_end/closure middle_end/flambda \
diff --git a/debian/patches/series b/debian/patches/series
index 6da62215..f7cc4551 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -4,3 +4,4 @@ Do-not-error-on-warnings-in-autoconf.patch
 Use-CCLINKFLAGS-for-linking-all-executables-and-shar.patch
 Mark-test_compact_manydomains-as-multicore.patch
 Increase-the-amount-of-data-written-to-a-pipe-in-a-test.patch
+Compile-utils-config.-cmi-cmx-with-opaque.patch
diff --git a/debian/rules b/debian/rules
index 1aadd633..dee2d094 100755
--- a/debian/rules
+++ b/debian/rules
@@ -222,6 +222,8 @@ install-stamp-arch: install-stamp
 install-stamp:
 # Install OCaml
 	$(MAKE) install DESTDIR=$(CURDIR)/debian/tmp
+# Remove config.cmx so that it is not part of compiler-libs ABI
+	rm -f debian/tmp$(OCAML_STDLIB_DIR)/compiler-libs/config.cmx
 ifeq (,$(DEB_TEST_BUILD_PREFIX))
 # Remove Debian-specific file
 	rm -f debian/tmp$(OCAML_STDLIB_DIR)/ld.conf
-- 
2.30.2