[rpms/arbor] f45: fix: add patch to use system fmt

[Ankur Sinha (Ankur Sinha Gmail) <sanjay.ankur@gmail.com>]

            A new commit has been pushed.

            Repo   : rpms/arbor
            Branch : f45
            Commit : dc723081dd02d83c29521e496f84c834c22eee68
            Author : Ankur Sinha (Ankur Sinha Gmail) <sanjay.ankur@gmail.com>
            Date   : 2026-08-19T12:13:31+01:00
            Stats  : +36/-0 in 2 file(s)
            URL    : https://src.fedoraproject.org/rpms/arbor/c/dc723081dd02d83c29521e496f84c834c22eee68?branch=f45

            Log:
            fix: add patch to use system fmt

- Fixes rhbz#2433869

Assisted-by: opencode (DeepSeek V4 Flash)

---
diff --git a/0005-Use-system-fmt.patch b/0005-Use-system-fmt.patch
new file mode 100644
index 0000000..95a2cb7
--- /dev/null
+++ b/0005-Use-system-fmt.patch
@@ -0,0 +1,33 @@
+From 670389c2148c4975e82118c01f2bee6cbc2e3e40 Mon Sep 17 00:00:00 2001
+From: "Ankur Sinha (Ankur Sinha Gmail)" <sanjay.ankur@gmail.com>
+Date: Wed, 19 Aug 2026 10:38:31 +0100
+Subject: [PATCH] Use system fmt instead of CPM download
+
+find_package(fmt 12.1.0) fails on Fedora 44, where the system fmt is
+version 11.x, so CPM tries to download fmt 12.1.0 from GitHub at
+configure time, which fails in the offline buildroot. Use the system
+fmt without a version requirement instead; the fmt::fmt-header-only
+target used by arbor is provided by fmt-devel.
+---
+ CMakeLists.txt | 5 +----
+ 1 file changed, 1 insertion(+), 4 deletions(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index cef4f4a2..72ef717f 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -345,10 +345,7 @@ else()
+ endif()
+ install(TARGETS ext-pugixml EXPORT arbor-targets)
+ 
+-CPMFindPackage(NAME fmt
+-              GITHUB_REPOSITORY fmtlib/fmt
+-              VERSION 12.1.0
+-              GIT_TAG 12.1.0)
++find_package(fmt REQUIRED)
+ 
+ add_library(ext-gtest INTERFACE)
+ add_library(ext-bench INTERFACE)
+-- 
+2.55.0
+

diff --git a/arbor.spec b/arbor.spec
index acd961c..a1af269 100644
--- a/arbor.spec
+++ b/arbor.spec
@@ -68,6 +68,9 @@ Patch:          0002-Use-system-Random123.patch
 Patch:          0003-Use-system-GTest.patch
 # Add missing standard includes for GCC 16
 Patch:          0004-Add-missing-standard-includes-to-profiler.patch
+# Use system fmt instead of letting CPM download it (it tries to fetch
+# fmt 12.1.0, which is newer than the fmt 11 in Fedora 44)
+Patch:          0005-Use-system-fmt.patch
 
 # Random123 does not support:
 #   mips64r2 mips32r2 s390