Add GNUInstallDirs module to define GNU layout (#3976)

Provide CMAKE_INSTALL_* variables to help install files according
to the GNU standard layout:

  http://www.gnu.org/prep/standards/html_node/Directory-Variables.html

Modules/GNUInstallDirs.cmake

@@ -0,0 +1,166 @@
+# - Define the installation directories conforming to GNU standards.
+# This module defines installation directories, as described by GNU standards.
+# For more information about this standards, see the following site:
+# http://www.gnu.org/prep/standards/html_node/Directory-Variables.html
+#
+# Module defines variables for installation directories and for resulting paths
+# of this directories.
+#
+# Installation directories appointed to use during install. If such variable
+# contains relative path, during install resulting path will be created by
+# prepending it with CMAKE_INSTALL_PREFIX. If it contains absolute path, it
+# would be taken as is.
+# This variables only set if not defined already, thus allowing to override them
+# and are stored in cache.
+#   CMAKE_INSTALL_BINDIR              - user executables (bin)
+#   CMAKE_INSTALL_SBINDIR             - system admin executables (sbin)
+#   CMAKE_INSTALL_LIBEXECDIR          - program executables (libexec)
+#   CMAKE_INSTALL_SYSCONFDIR          - read-only single-machine data (etc)
+#   CMAKE_INSTALL_SHAREDSTATEDIR      - modifiable architecture-independent data (com)
+#   CMAKE_INSTALL_LOCALSTATEDIR       - modifiable single-machine data (var)
+#   CMAKE_INSTALL_LIBDIR              - object code libraries (lib)
+#   CMAKE_INSTALL_INCLUDEDIR          - C header files (include)
+#   CMAKE_INSTALL_OLDINCLUDEDIR       - C header files for non-gcc (/usr/include)
+#   CMAKE_INSTALL_DATAROOTDIR         - read-only architecture-independent data root (share)
+#   CMAKE_INSTALL_DATADIR             - read-only architecture-independent data (DATAROOTDIR)
+#   CMAKE_INSTALL_INFODIR             - info documentation (DATAROOTDIR/info)
+#   CMAKE_INSTALL_LOCALEDIR           - locale-dependent data (DATAROOTDIR/locale)
+#   CMAKE_INSTALL_MANDIR              - man documentation (DATAROOTDIR/man)
+#   CMAKE_INSTALL_DOCDIR              - documentation root (DATAROOTDIR/doc/PROJECT_NAME)
+# Resulting directories derived from installation directories and always
+# contains absolute paths.
+# This variables computed in runtime and not stored in cache.
+#   CMAKE_INSTALL_FULL_BINDIR         - user executables full path (PREFIX/BINDIR)
+#   CMAKE_INSTALL_FULL_SBINDIR        - system admin executables full path (PREFIX/SBINDIR)
+#   CMAKE_INSTALL_FULL_LIBEXECDIR     - program executables full path (PREFIX/LIBEXECDIR)
+#   CMAKE_INSTALL_FULL_SYSCONFDIR     - read-only single-machine data fill path (PREFIX/SYSCONFDIR)
+#   CMAKE_INSTALL_FULL_SHAREDSTATEDIR - modifiable architecture-independent data full path (PREFIX/SHAREDSTATEDIR)
+#   CMAKE_INSTALL_FULL_LOCALSTATEDIR  - modifiable single-machine data full path (PREFIX/LOCALSTATEDIR)
+#   CMAKE_INSTALL_FULL_LIBDIR         - object code libraries full path (PREFIX/LIBDIR)
+#   CMAKE_INSTALL_FULL_INCLUDEDIR     - C header files full path (PREFIX/INCLUDEDIR)
+#   CMAKE_INSTALL_FULL_OLDINCLUDEDIR  - C header files for non-gcc full path (/usr/include)
+#   CMAKE_INSTALL_FULL_DATAROOTDIR    - read-only architecture-independent data root full path (PREFIX/DATAROOTDIR)
+#   CMAKE_INSTALL_FULL_DATADIR        - read-only architecture-independent data full path (PREFIX/DATADIR)
+#   CMAKE_INSTALL_FULL_INFODIR        - info documentation full path (PREFIX/INFODIR)
+#   CMAKE_INSTALL_FULL_LOCALEDIR      - locale-dependent data full path (PREFIX/LOCALEDIR)
+#   CMAKE_INSTALL_FULL_MANDIR         - man documentation full path (PREFIX/MANDIR)
+#   CMAKE_INSTALL_FULL_DOCDIR         - documentation root full path (PREFIX/DOCDIR)
+
+#=============================================================================
+# Copyright 2011 Nikita Krupen'ko <[email protected]>
+#
+# Distributed under the OSI-approved BSD License (the "License");
+# see accompanying file Copyright.txt for details.
+#
+# This software is distributed WITHOUT ANY WARRANTY; without even the
+# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+# See the License for more information.
+#=============================================================================
+# (To distribute this file outside of CMake, substitute the full
+#  License text for the above reference.)
+
+# Installation directories
+#
+if(NOT DEFINED CMAKE_INSTALL_BINDIR)
+  set(CMAKE_INSTALL_BINDIR "bin" CACHE PATH "user executables (bin)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_SBINDIR)
+  set(CMAKE_INSTALL_SBINDIR "sbin" CACHE PATH "system admin executables (sbin)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_LIBEXECDIR)
+  set(CMAKE_INSTALL_LIBEXECDIR "libexec" CACHE PATH "program executables (libexec)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_SYSCONFDIR)
+  set(CMAKE_INSTALL_SYSCONFDIR "etc" CACHE PATH "read-only single-machine data (etc)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_SHAREDSTATEDIR)
+  set(CMAKE_INSTALL_SHAREDSTATEDIR "com" CACHE PATH "modifiable architecture-independent data (com)")
+endif()
+
+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)
+  set(CMAKE_INSTALL_LIBDIR "lib" CACHE PATH "object code libraries (lib)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_INCLUDEDIR)
+  set(CMAKE_INSTALL_INCLUDEDIR "include" CACHE PATH "C header files (include)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_OLDINCLUDEDIR)
+  set(CMAKE_INSTALL_OLDINCLUDEDIR "/usr/include" CACHE PATH "C header files for non-gcc (/usr/include)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_DATAROOTDIR)
+  set(CMAKE_INSTALL_DATAROOTDIR "share" CACHE PATH "read-only architecture-independent data root (share)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_DATADIR)
+  set(CMAKE_INSTALL_DATADIR "${CMAKE_INSTALL_DATAROOTDIR}" CACHE PATH "read-only architecture-independent data (DATAROOTDIR)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_INFODIR)
+  set(CMAKE_INSTALL_INFODIR "${CMAKE_INSTALL_DATAROOTDIR}/info" CACHE PATH "info documentation (DATAROOTDIR/info)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_LOCALEDIR)
+  set(CMAKE_INSTALL_LOCALEDIR "${CMAKE_INSTALL_DATAROOTDIR}/locale" CACHE PATH "locale-dependent data (DATAROOTDIR/locale)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_MANDIR)
+  set(CMAKE_INSTALL_MANDIR "${CMAKE_INSTALL_DATAROOTDIR}/man" CACHE PATH "man documentation (DATAROOTDIR/man)")
+endif()
+
+if(NOT DEFINED CMAKE_INSTALL_DOCDIR)
+  set(CMAKE_INSTALL_DOCDIR "${CMAKE_INSTALL_DATAROOTDIR}/doc/${PROJECT_NAME}" CACHE PATH "documentation root (DATAROOTDIR/doc/PROJECT_NAME)")
+endif()
+
+mark_as_advanced(
+  CMAKE_INSTALL_BINDIR
+  CMAKE_INSTALL_SBINDIR
+  CMAKE_INSTALL_LIBEXECDIR
+  CMAKE_INSTALL_SYSCONFDIR
+  CMAKE_INSTALL_SHAREDSTATEDIR
+  CMAKE_INSTALL_LOCALSTATEDIR
+  CMAKE_INSTALL_LIBDIR
+  CMAKE_INSTALL_INCLUDEDIR
+  CMAKE_INSTALL_OLDINCLUDEDIR
+  CMAKE_INSTALL_DATAROOTDIR
+  CMAKE_INSTALL_DATADIR
+  CMAKE_INSTALL_INFODIR
+  CMAKE_INSTALL_LOCALEDIR
+  CMAKE_INSTALL_MANDIR
+  CMAKE_INSTALL_DOCDIR
+  )
+
+# Result directories
+#
+foreach(dir
+    BINDIR
+    SBINDIR
+    LIBEXECDIR
+    SYSCONFDIR
+    SHAREDSTATEDIR
+    LOCALSTATEDIR
+    LIBDIR
+    INCLUDEDIR
+    OLDINCLUDEDIR
+    DATAROOTDIR
+    DATADIR
+    INFODIR
+    LOCALEDIR
+    MANDIR
+    DOCDIR
+    )
+  if(NOT IS_ABSOLUTE ${CMAKE_INSTALL_${dir}})
+    set(CMAKE_INSTALL_FULL_${dir} "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_${dir}}")
+  else()
+    set(CMAKE_INSTALL_FULL_${dir} "${CMAKE_INSTALL_${dir}}")
+  endif()
+endforeach()