arpack: Use upstream patch

mingw-w64-arpack/0002-parpack-optional-installation.patch

@@ -1,19 +1,35 @@
-From f76b9267392f77716d205394108e1d9fe156c416 Mon Sep 17 00:00:00 2001
+From de353fb99b35ee15bc652c217a7475590ac56612 Mon Sep 17 00:00:00 2001
 From: =?UTF-8?q?Markus=20M=C3=BCtzel?= <markus.muetzel@gmx.de>
 Date: Sat, 5 Sep 2026 18:42:19 +0200
-Subject: [PATCH] parpack: optional installation
+Subject: [PATCH] Support optional installation of parpack in CMake config
+ files
 
-In MSYS2, the parpack library is split into a separate package.
+Some distributions (e.g., Debian/Ubuntu or MSYS2) split the parpack library into
+a separate package.
+That leads to issues if their arpack package is installed but their parpack
+package is not.
 
-Support using the CMake config files in the case where the parpack package is
-not installed.
+Auto-generated CMake target files check whether the respective files actually
+exist on disc. Because both the arpack import target and the parpack import
+target are included in the same auto-generated CMake target file of arpack-ng
+(if it was configured to be built parpack), that leads to a fatal error when
+attempting to import the arpack CMake target in downstream projects while the
+parpack files are not installed.
+
+Support using the CMake config files in the case where distributions split
+parpack into a separate package, and that package is not installed.
+That is done by auto-generating a separate CMake target file for parpack,
+and checking whether it exists before including it in the CMake config file.
+Distributors can then move the CMake target file for parpack to their
+separate package.
 ---
+ CHANGES                        | 1 +
  CMakeLists.txt                 | 7 ++++++-
- cmake/arpackng-config.cmake.in | 4 ++++
- 2 files changed, 10 insertions(+), 1 deletion(-)
+ cmake/arpackng-config.cmake.in | 6 +++++-
+ 3 files changed, 12 insertions(+), 2 deletions(-)
 
 diff --git a/CMakeLists.txt b/CMakeLists.txt
-index d15ff0e..c46b63f 100644
+index d15ff0ecf..7a3273f83 100644
 --- a/CMakeLists.txt
 +++ b/CMakeLists.txt
 @@ -860,7 +860,7 @@ install(FILES "${PROJECT_BINARY_DIR}/SRC/arpack${LIBSUFFIX}${ITF64SUFFIX}.pc"
@@ -32,26 +48,32 @@ index d15ff0e..c46b63f 100644
 +if (MPI)
 +  install(EXPORT parpackngTargets
 +    DESTINATION "${ARPACK_INSTALL_CMAKEDIR}"
-+)
++  )
 +endif()
  # Provide find_package for arpack-ng to users.
  configure_file(cmake/arpackng-config.cmake.in "${PROJECT_BINARY_DIR}/arpackng-config.cmake" @ONLY)
  configure_file(cmake/arpackng-config-version.cmake.in "${PROJECT_BINARY_DIR}/arpackng-config-version.cmake" @ONLY)
 diff --git a/cmake/arpackng-config.cmake.in b/cmake/arpackng-config.cmake.in
-index bafa3fe..72e5458 100644
+index bafa3fed1..968ff6f4c 100644
 --- a/cmake/arpackng-config.cmake.in
 +++ b/cmake/arpackng-config.cmake.in
+@@ -24,7 +24,7 @@ if (NOT @BUILD_SHARED_LIBS@)
+ 	if (@ICB@)
+ 		enable_language(Fortran)
+ 	endif()
+-	if (@MPI@)
++	if (EXISTS "${CMAKE_CURRENT_LIST_DIR}/parpackngTargets.cmake")
+ 		include(FindMPI)
+ 		if (NOT TARGET MPI::Fortran)
+ 			find_dependency(MPI REQUIRED COMPONENTS Fortran)
 @@ -34,6 +34,10 @@ endif()
 
  include("${CMAKE_CURRENT_LIST_DIR}/arpackngTargets.cmake")
 
 +if(EXISTS "${CMAKE_CURRENT_LIST_DIR}/parpackngTargets.cmake")
-+  include("${CMAKE_CURRENT_LIST_DIR}/parpackngTargets.cmake")
++	include("${CMAKE_CURRENT_LIST_DIR}/parpackngTargets.cmake")
 +endif()
 +
  add_library(ARPACK::ARPACK ALIAS arpack)
  if (TARGET parpack)
  	add_library(PARPACK::PARPACK ALIAS parpack)
--- 
-2.51.0.windows.2
-

mingw-w64-arpack/PKGBUILD

@@ -10,7 +10,7 @@ pkgname=("${MINGW_PACKAGE_PREFIX}-${_realname}"
          "${MINGW_PACKAGE_PREFIX}-${_realname}64"
          $([[ "${CARCH}" != "x86_64" ]] || echo "${MINGW_PACKAGE_PREFIX}-p${_realname}"))
 pkgver=3.9.1
-pkgrel=8
+pkgrel=9
 pkgdesc="Fortran77 subroutines designed to solve large scale eigenvalue problems (mingw-w64)"
 arch=('any')
 mingw_arch=('mingw64' 'ucrt64' 'clang64' 'clangarm64')
@@ -31,7 +31,7 @@ source=(https://github.com/opencollab/arpack-ng/archive/${pkgver}/${_realname}-$
         0002-parpack-optional-installation.patch)
 sha256sums=('f6641deb07fa69165b7815de9008af3ea47eb39b2bb97521fbf74c97aba6e844'
             '8bf923fb87d51bb313fc154d070941b932e74d6b7094e699fa84da6a913e3817'
-            '4247a559c9cf6c158107648534c56af756013dc4ba9bbdbd6741f0618084a849')
+            '2e7abfbd58eaab150e097d2c9787ee83b2da43bfa9f6d0e4a5425d3dd46a86f1')
 
 # Helper macros to help make tasks easier #
 apply_patch_with_msg() {