Fix misinterpretation of Debian Policy on LIBEXECDIR

debian/patches/0004-Fix-misinterpretation-of-Debian-Policy-on-LIBEXECDIR.patch

@@ -0,0 +1,70 @@
+From: =?utf-8?q?Timo_R=C3=B6hling?= <roehling@debian.org>
+Date: Thu, 7 Oct 2021 20:45:32 +0200
+Subject: Fix misinterpretation of Debian Policy on LIBEXECDIR
+
+Forwarded: https://gitlab.kitware.com/cmake/cmake/-/merge_requests/6607
+
+The Debian Policy builds upon FHS 3.0 and permits installing to
+/usr/libexec. While Policy does grant an additional exception for
+applications to use a single subdirectory of /usr/lib/<triplet>, this is
+not meant to replace /usr/libexec as valid target.
+---
+ Modules/GNUInstallDirs.cmake                        | 15 ++-------------
+ Tests/RunCMake/GNUInstallDirs/Usr-Debian-stderr.txt |  4 ++--
+ 2 files changed, 4 insertions(+), 15 deletions(-)
+
+diff --git a/Modules/GNUInstallDirs.cmake b/Modules/GNUInstallDirs.cmake
+index ead55ca..4aaad79 100644
+--- a/Modules/GNUInstallDirs.cmake
++++ b/Modules/GNUInstallDirs.cmake
+@@ -180,6 +180,8 @@ _GNUInstallDirs_cache_path(CMAKE_INSTALL_BINDIR "bin"
+   "User executables (bin)")
+ _GNUInstallDirs_cache_path(CMAKE_INSTALL_SBINDIR "sbin"
+   "System admin executables (sbin)")
++_GNUInstallDirs_cache_path(CMAKE_INSTALL_LIBEXECDIR "libexec"
++  "Program executables (libexec)")
+ _GNUInstallDirs_cache_path(CMAKE_INSTALL_SYSCONFDIR "etc"
+   "Read-only single-machine data (etc)")
+ _GNUInstallDirs_cache_path(CMAKE_INSTALL_SHAREDSTATEDIR "com"
+@@ -274,19 +276,6 @@ set(_GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX "${CMAKE_INSTALL_PREFIX}" CACHE IN
+ unset(_libdir_set)
+ unset(__LAST_LIBDIR_DEFAULT)
+ 
+-if(CMAKE_SYSTEM_NAME MATCHES "^(Linux|kFreeBSD|GNU)$"
+-    AND NOT CMAKE_CROSSCOMPILING
+-    AND NOT EXISTS "/etc/arch-release"
+-    AND EXISTS "/etc/debian_version" # is this a debian system ?
+-    AND "${CMAKE_INSTALL_PREFIX}" MATCHES "^/usr/?$")
+-  # see https://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.html#usrlibexec
+-  # and https://www.debian.org/doc/debian-policy/ch-opersys#file-system-structure (section 9.1.1 bullet point 4)
+-  _GNUInstallDirs_cache_path(CMAKE_INSTALL_LIBEXECDIR "${CMAKE_INSTALL_LIBDIR}"
+-    "Program executables (${CMAKE_INSTALL_LIBDIR})")
+-else()
+-  _GNUInstallDirs_cache_path(CMAKE_INSTALL_LIBEXECDIR "libexec"
+-    "Program executables (libexec)")
+-endif()
+ _GNUInstallDirs_cache_path(CMAKE_INSTALL_INCLUDEDIR "include"
+   "C header files (include)")
+ _GNUInstallDirs_cache_path(CMAKE_INSTALL_OLDINCLUDEDIR "/usr/include"
+diff --git a/Tests/RunCMake/GNUInstallDirs/Usr-Debian-stderr.txt b/Tests/RunCMake/GNUInstallDirs/Usr-Debian-stderr.txt
+index 89578ee..c38006c 100644
+--- a/Tests/RunCMake/GNUInstallDirs/Usr-Debian-stderr.txt
++++ b/Tests/RunCMake/GNUInstallDirs/Usr-Debian-stderr.txt
+@@ -5,7 +5,7 @@ CMAKE_INSTALL_DOCDIR='share/doc/Usr'
+ CMAKE_INSTALL_INCLUDEDIR='include'
+ CMAKE_INSTALL_INFODIR='share/info'
+ CMAKE_INSTALL_LIBDIR='lib/arch'
+-CMAKE_INSTALL_LIBEXECDIR='lib/arch'
++CMAKE_INSTALL_LIBEXECDIR='libexec'
+ CMAKE_INSTALL_LOCALEDIR='share/locale'
+ CMAKE_INSTALL_LOCALSTATEDIR='var'
+ CMAKE_INSTALL_RUNSTATEDIR='var/run'
+@@ -20,7 +20,7 @@ CMAKE_INSTALL_FULL_DOCDIR='/usr/share/doc/Usr'
+ CMAKE_INSTALL_FULL_INCLUDEDIR='/usr/include'
+ CMAKE_INSTALL_FULL_INFODIR='/usr/share/info'
+ CMAKE_INSTALL_FULL_LIBDIR='/usr/lib/arch'
+-CMAKE_INSTALL_FULL_LIBEXECDIR='/usr/lib/arch'
++CMAKE_INSTALL_FULL_LIBEXECDIR='/usr/libexec'
+ CMAKE_INSTALL_FULL_LOCALEDIR='/usr/share/locale'
+ CMAKE_INSTALL_FULL_LOCALSTATEDIR='/var'
+ CMAKE_INSTALL_FULL_RUNSTATEDIR='/var/run'

debian/patches/series

@@ -1,3 +1,4 @@
 0001-Fix-cross-compilation-with-MPI.patch
 0002-Prefer-Debian-default-version-of-Python.patch
 0003-Fix-RunCMake.CPack_DEB.EXTRA-on-Debian-non-Linux-OSe.patch
+0004-Fix-misinterpretation-of-Debian-Policy-on-LIBEXECDIR.patch