From 06be6812a674e23abc9e24fa2fbd7a7c20684c74 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Mon, 3 Jun 2024 14:08:37 -0400
Subject: [PATCH] Create and install a `nix-util.pc`

Before, `-lnixutil` was just stuck in `nix-store.pc`, but that doesn't
seem so nice.

This prepares us to distribute `libnixutil` in a separate package if we
want, but it should be a good change either way. I suspect it wasn't
done before because libutil was an extra unstable interface, but I don't
think we need worry about that. *All* the C++ is less stable than the C
(or that's the goal at least).

For what it's worth, Lix also created this pkg-config file *en passant*
during their rename:
https://git.lix.systems/lix-project/lix/commit/c97e17144e0d0b666d7b79d8b4b0d581bfdf373b#diff-3c4f60cc44a0e35444c7f45331cfa50f76637118
---
 src/libstore/nix-store.pc.in | 3 ++-
 src/libutil/local.mk         | 2 ++
 src/libutil/nix-util.pc.in   | 9 +++++++++
 3 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 src/libutil/nix-util.pc.in

diff --git a/src/libstore/nix-store.pc.in b/src/libstore/nix-store.pc.in
index dc42d0bca..cd3f2b8da 100644
--- a/src/libstore/nix-store.pc.in
+++ b/src/libstore/nix-store.pc.in
@@ -5,5 +5,6 @@ includedir=@includedir@
 Name: Nix
 Description: Nix Package Manager
 Version: @PACKAGE_VERSION@
-Libs: -L${libdir} -lnixstore -lnixutil
+Requires: nix-util
+Libs: -L${libdir} -lnixstore
 Cflags: -I${includedir}/nix -std=c++2a
diff --git a/src/libutil/local.mk b/src/libutil/local.mk
index 5cd8d4ac8..e9b498e65 100644
--- a/src/libutil/local.mk
+++ b/src/libutil/local.mk
@@ -40,3 +40,5 @@ $(foreach i, $(wildcard $(d)/signature/*.hh), \
 ifeq ($(HAVE_LIBCPUID), 1)
   libutil_LDFLAGS += -lcpuid
 endif
+
+$(eval $(call install-file-in, $(buildprefix)$(d)/nix-util.pc, $(libdir)/pkgconfig, 0644))
diff --git a/src/libutil/nix-util.pc.in b/src/libutil/nix-util.pc.in
new file mode 100644
index 000000000..85bb1e70e
--- /dev/null
+++ b/src/libutil/nix-util.pc.in
@@ -0,0 +1,9 @@
+prefix=@prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: Nix
+Description: Nix Package Manager
+Version: @PACKAGE_VERSION@
+Libs: -L${libdir} -lnixutil
+Cflags: -I${includedir}/nix -std=c++2a