Update to latest GNUInstallDirs cmake module

This version correctly detects debians multiarch lib handling and
lets us remove the manually set CMAKE_LIB_INSTALL_DIRS from the rules
file.

1 files changed, 117 insertions, 40 deletions

diff --git a/cmake/modules/GNUInstallDirs.cmake b/cmake/modules/GNUInstallDirs.cmake
index a114dcb2e..d868cb31c 100644
--- a/cmake/modules/GNUInstallDirs.cmake
+++ b/cmake/modules/GNUInstallDirs.cmake
@@ -1,32 +1,49 @@
-# - Define GNU standard installation directories
+#.rst:
+# GNUInstallDirs
+# --------------
+#
+# Define GNU standard installation directories
+#
 # Provides install directory variables as defined for GNU software:
-#  http://www.gnu.org/prep/standards/html_node/Directory-Variables.html
+#
+# ::
+#
+#   http://www.gnu.org/prep/standards/html_node/Directory-Variables.html
+#
 # Inclusion of this module defines the following variables:
-#  CMAKE_INSTALL_<dir>      - destination for files of a given type
-#  CMAKE_INSTALL_FULL_<dir> - corresponding absolute path
+#
+# ::
+#
+#   CMAKE_INSTALL_<dir>      - destination for files of a given type
+#   CMAKE_INSTALL_FULL_<dir> - corresponding absolute path
+#
 # where <dir> is one of:
-#  BINDIR           - user executables (bin)
-#  SBINDIR          - system admin executables (sbin)
-#  LIBEXECDIR       - program executables (libexec)
-#  SYSCONFDIR       - read-only single-machine data (etc)
-#  SHAREDSTATEDIR   - modifiable architecture-independent data (com)
-#  LOCALSTATEDIR    - modifiable single-machine data (var)
-#  LIBDIR           - object code libraries (lib or lib64)
-#  INCLUDEDIR       - C header files (include)
-#  OLDINCLUDEDIR    - C header files for non-gcc (/usr/include)
-#  DATAROOTDIR      - read-only architecture-independent data root (share)
-#  DATADIR          - read-only architecture-independent data (DATAROOTDIR)
-#  INFODIR          - info documentation (DATAROOTDIR/info)
-#  LOCALEDIR        - locale-dependent data (DATAROOTDIR/locale)
-#  MANDIR           - man documentation (DATAROOTDIR/man)
-#  DOCDIR           - documentation root (DATAROOTDIR/doc/PROJECT_NAME)
-# Each CMAKE_INSTALL_<dir> value may be passed to the DESTINATION options of
-# install() commands for the corresponding file type.  If the includer does
-# not define a value the above-shown default will be used and the value will
-# appear in the cache for editing by the user.
-# Each CMAKE_INSTALL_FULL_<dir> value contains an absolute path constructed
-# from the corresponding destination by prepending (if necessary) the value
-# of CMAKE_INSTALL_PREFIX.
+#
+# ::
+#
+#   BINDIR           - user executables (bin)
+#   SBINDIR          - system admin executables (sbin)
+#   LIBEXECDIR       - program executables (libexec)
+#   SYSCONFDIR       - read-only single-machine data (etc)
+#   SHAREDSTATEDIR   - modifiable architecture-independent data (com)
+#   LOCALSTATEDIR    - modifiable single-machine data (var)
+#   LIBDIR           - object code libraries (lib or lib64 or lib/<multiarch-tuple> on Debian)
+#   INCLUDEDIR       - C header files (include)
+#   OLDINCLUDEDIR    - C header files for non-gcc (/usr/include)
+#   DATAROOTDIR      - read-only architecture-independent data root (share)
+#   DATADIR          - read-only architecture-independent data (DATAROOTDIR)
+#   INFODIR          - info documentation (DATAROOTDIR/info)
+#   LOCALEDIR        - locale-dependent data (DATAROOTDIR/locale)
+#   MANDIR           - man documentation (DATAROOTDIR/man)
+#   DOCDIR           - documentation root (DATAROOTDIR/doc/PROJECT_NAME)
+#
+# Each CMAKE_INSTALL_<dir> value may be passed to the DESTINATION
+# options of install() commands for the corresponding file type.  If the
+# includer does not define a value the above-shown default will be used
+# and the value will appear in the cache for editing by the user.  Each
+# CMAKE_INSTALL_FULL_<dir> value contains an absolute path constructed
+# from the corresponding destination by prepending (if necessary) the
+# value of CMAKE_INSTALL_PREFIX.
 
 #=============================================================================
 # Copyright 2011 Nikita Krupen'ko <krnekit@gmail.com>
@@ -68,30 +85,90 @@ if(NOT DEFINED CMAKE_INSTALL_LOCALSTATEDIR)
   set(CMAKE_INSTALL_LOCALSTATEDIR "var" CACHE PATH "modifiable single-machine data (var)")
 endif()
 
-if(NOT DEFINED CMAKE_INSTALL_LIBDIR)
+# We check if the variable was manually set and not cached, in order to
+# allow projects to set the values as normal variables before including
+# GNUInstallDirs to avoid having the entries cached or user-editable. It
+# replaces the "if(NOT DEFINED CMAKE_INSTALL_XXX)" checks in all the
+# other cases.
+# If CMAKE_INSTALL_LIBDIR is defined, if _libdir_set is false, then the
+# variable is a normal one, otherwise it is a cache one.
+get_property(_libdir_set CACHE CMAKE_INSTALL_LIBDIR PROPERTY TYPE SET)
+if(NOT DEFINED CMAKE_INSTALL_LIBDIR OR (_libdir_set
+    AND DEFINED _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX
+    AND NOT "${_GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX}" STREQUAL "${CMAKE_INSTALL_PREFIX}"))
+  # If CMAKE_INSTALL_LIBDIR is not defined, it is always executed.
+  # Otherwise:
+  #  * if _libdir_set is false it is not executed (meaning that it is
+  #    not a cache variable)
+  #  * if _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX is not defined it is
+  #    not executed
+  #  * if _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX and
+  #    CMAKE_INSTALL_PREFIX are the same string it is not executed.
+  #    _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX is updated after the
+  #    execution, of this part of code, therefore at the next inclusion
+  #    of the file, CMAKE_INSTALL_LIBDIR is defined, and the 2 strings
+  #    are equal, meaning that the if is not executed the code the
+  #    second time.
+
   set(_LIBDIR_DEFAULT "lib")
   # Override this default 'lib' with 'lib64' iff:
   #  - we are on Linux system but NOT cross-compiling
   #  - we are NOT on debian
   #  - we are on a 64 bits system
   # reason is: amd64 ABI: http://www.x86-64.org/documentation/abi.pdf
-  # Note that the future of multi-arch handling may be even
-  # more complicated than that: http://wiki.debian.org/Multiarch
-  if(CMAKE_SYSTEM_NAME MATCHES "Linux"
-      AND NOT CMAKE_CROSSCOMPILING
-      AND NOT EXISTS "/etc/debian_version")
-    if(NOT DEFINED CMAKE_SIZEOF_VOID_P)
-      message(AUTHOR_WARNING
-        "Unable to determine default CMAKE_INSTALL_LIBDIR directory because no target architecture is known. "
-        "Please enable at least one language before including GNUInstallDirs.")
-    else()
-      if("${CMAKE_SIZEOF_VOID_P}" EQUAL "8")
-        set(_LIBDIR_DEFAULT "lib64")
+  # For Debian with multiarch, use 'lib/${CMAKE_LIBRARY_ARCHITECTURE}' if
+  # CMAKE_LIBRARY_ARCHITECTURE is set (which contains e.g. "i386-linux-gnu"
+  # and CMAKE_INSTALL_PREFIX is "/usr"
+  # See http://wiki.debian.org/Multiarch
+  if(DEFINED _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX)
+    set(__LAST_LIBDIR_DEFAULT "lib")
+    # __LAST_LIBDIR_DEFAULT is the default value that we compute from
+    # _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX, not a cache entry for
+    # the value that was last used as the default.
+    # This value is used to figure out whether the user changed the
+    # CMAKE_INSTALL_LIBDIR value manually, or if the value was the
+    # default one. When CMAKE_INSTALL_PREFIX changes, the value is
+    # updated to the new default, unless the user explicitly changed it.
+  endif()
+  if(CMAKE_SYSTEM_NAME MATCHES "^(Linux|kFreeBSD|GNU)$"
+      AND NOT CMAKE_CROSSCOMPILING)
+    if (EXISTS "/etc/debian_version") # is this a debian system ?
+      if(CMAKE_LIBRARY_ARCHITECTURE)
+        if("${CMAKE_INSTALL_PREFIX}" MATCHES "^/usr/?$")
+          set(_LIBDIR_DEFAULT "lib/${CMAKE_LIBRARY_ARCHITECTURE}")
+        endif()
+        if(DEFINED _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX
+            AND "${_GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX}" MATCHES "^/usr/?$")
+          set(__LAST_LIBDIR_DEFAULT "lib/${CMAKE_LIBRARY_ARCHITECTURE}")
+        endif()
+      endif()
+    else() # not debian, rely on CMAKE_SIZEOF_VOID_P:
+      if(NOT DEFINED CMAKE_SIZEOF_VOID_P)
+        message(AUTHOR_WARNING
+          "Unable to determine default CMAKE_INSTALL_LIBDIR directory because no target architecture is known. "
+          "Please enable at least one language before including GNUInstallDirs.")
+      else()
+        if("${CMAKE_SIZEOF_VOID_P}" EQUAL "8")
+          set(_LIBDIR_DEFAULT "lib64")
+          if(DEFINED _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX)
+            set(__LAST_LIBDIR_DEFAULT "lib64")
+          endif()
+        endif()
       endif()
     endif()
   endif()
-  set(CMAKE_INSTALL_LIBDIR "${_LIBDIR_DEFAULT}" CACHE PATH "object code libraries (${_LIBDIR_DEFAULT})")
+  if(NOT DEFINED CMAKE_INSTALL_LIBDIR)
+    set(CMAKE_INSTALL_LIBDIR "${_LIBDIR_DEFAULT}" CACHE PATH "object code libraries (${_LIBDIR_DEFAULT})")
+  elseif(DEFINED __LAST_LIBDIR_DEFAULT
+      AND "${__LAST_LIBDIR_DEFAULT}" STREQUAL "${CMAKE_INSTALL_LIBDIR}")
+    set_property(CACHE CMAKE_INSTALL_LIBDIR PROPERTY VALUE "${_LIBDIR_DEFAULT}")
+  endif()
 endif()
+# Save for next run
+set(_GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX "${CMAKE_INSTALL_PREFIX}" CACHE INTERNAL "CMAKE_INSTALL_PREFIX during last run")
+unset(_libdir_set)
+unset(__LAST_LIBDIR_DEFAULT)
+
 
 if(NOT DEFINED CMAKE_INSTALL_INCLUDEDIR)
   set(CMAKE_INSTALL_INCLUDEDIR "include" CACHE PATH "C header files (include)")