CMake: refactor and reformat CMake files

- raise minimum CMake version from 2.6.3 to 3.2.3 (Jun 01, 2015)
- indent all CMake files according to the CMP (2 col.)
- refactor FLTK version number definitions and usage
- unify CMake and autoconf/configure variable names:
  - FL_VERSION -> FLTK_VERSION
  - FL_MAJOR_VERSION -> FLTK_VERSION_MAJOR
  - etc. for _MINOR_ and _PATCH_, respectively
  - note: this does not affect FL_VERSION etc. in source code
- generate "export headers" for all libraries (experimental: OFF)
- port some forgotten goodies from branch-1.3 to master
- merge and improve macro 'create_example' (WIP)
- remove "temporary" options and code for older CMake versions
- include and use 'GenerateExportHeader' (experimental, WIP: OFF)
  - note: created header files are not yet used
- build only *one* DLL with Visual Studio (tested, works)
  - similar to the bundled IDE projects in 1.3.x
- add some dynamically linked test/demo programs ('*-shared')
  if shared libraries are built (WIP)
- split 'macros.cmake': use one file per macro

1 files changed, 66 insertions, 55 deletions

diff --git a/CMake/install.cmake b/CMake/install.cmake
index 0ab8e6073..c01f19d4d 100644
--- a/CMake/install.cmake
+++ b/CMake/install.cmake
@@ -2,7 +2,7 @@
 # Main CMakeLists.txt to build the FLTK project using CMake (www.cmake.org)
 # Written by Michael Surette
 #
-# Copyright 1998-2018 by Bill Spitzak and others.
+# Copyright 1998-2020 by Bill Spitzak and others.
 #
 # This library is free software. Distribution and use rights are outlined in
 # the file "COPYING" which should have been included with this file.  If this
@@ -25,92 +25,103 @@ configure_file(
   "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake"
   @ONLY
 )
-add_custom_target(uninstall
+add_custom_target (uninstall
   "${CMAKE_COMMAND}" -P "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake"
 )
 
-install(DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/FL
-   DESTINATION ${FLTK_INCLUDEDIR} USE_SOURCE_PERMISSIONS
-   PATTERN ".svn" EXCLUDE
+install (DIRECTORY
+  ${CMAKE_CURRENT_SOURCE_DIR}/FL
+  DESTINATION ${FLTK_INCLUDEDIR} USE_SOURCE_PERMISSIONS
 )
 
-install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/FL
-   DESTINATION ${FLTK_INCLUDEDIR} USE_SOURCE_PERMISSIONS
+install (DIRECTORY
+  ${CMAKE_CURRENT_BINARY_DIR}/FL
+  DESTINATION ${FLTK_INCLUDEDIR} USE_SOURCE_PERMISSIONS
 )
 
-if(OPTION_CREATE_LINKS)
-   install(SCRIPT ${CMAKE_CURRENT_BINARY_DIR}/install-symlinks.cmake)
-endif(OPTION_CREATE_LINKS)
+if (OPTION_CREATE_LINKS)
+  install (SCRIPT ${CMAKE_CURRENT_BINARY_DIR}/install-symlinks.cmake)
+endif (OPTION_CREATE_LINKS)
 
 # generate FLTKConfig.cmake for installed directory use
-set(INCLUDE_DIRS ${CMAKE_INSTALL_PREFIX}/include)
+set (INCLUDE_DIRS ${CMAKE_INSTALL_PREFIX}/include)
 
-set(CONFIG_PATH ${CMAKE_INSTALL_PREFIX}/${FLTK_CONFIG_PATH})
+set (CONFIG_PATH ${CMAKE_INSTALL_PREFIX}/${FLTK_CONFIG_PATH})
 
-install(EXPORT FLTK-Targets
-   DESTINATION ${FLTK_CONFIG_PATH}
-   FILE FLTK-Targets.cmake
+install (EXPORT FLTK-Targets
+  DESTINATION ${FLTK_CONFIG_PATH}
+  FILE FLTK-Targets.cmake
 )
 
 configure_file(
-   ${CMAKE_CURRENT_SOURCE_DIR}/CMake/FLTKConfig.cmake.in
-   ${CMAKE_CURRENT_BINARY_DIR}/etc/FLTKConfig.cmake
-   @ONLY
+  ${CMAKE_CURRENT_SOURCE_DIR}/CMake/FLTKConfig.cmake.in
+  ${CMAKE_CURRENT_BINARY_DIR}/etc/FLTKConfig.cmake
+  @ONLY
+)
+
+install (FILES
+  ${CMAKE_CURRENT_BINARY_DIR}/etc/FLTKConfig.cmake
+  DESTINATION ${FLTK_CONFIG_PATH}
 )
 
-install(FILES ${CMAKE_CURRENT_BINARY_DIR}/etc/FLTKConfig.cmake
-   DESTINATION ${FLTK_CONFIG_PATH}
+install (FILES
+  ${CMAKE_CURRENT_SOURCE_DIR}/CMake/FLTK-Functions.cmake
+  DESTINATION ${FLTK_CONFIG_PATH}
 )
 
 configure_file(
-   ${CMAKE_CURRENT_SOURCE_DIR}/CMake/UseFLTK.cmake.in
-   ${CMAKE_CURRENT_BINARY_DIR}/etc/UseFLTK.cmake
-   @ONLY
+  ${CMAKE_CURRENT_SOURCE_DIR}/CMake/UseFLTK.cmake.in
+  ${CMAKE_CURRENT_BINARY_DIR}/etc/UseFLTK.cmake
+  @ONLY
 )
 
-install(FILES ${CMAKE_CURRENT_BINARY_DIR}/etc/UseFLTK.cmake
-   DESTINATION ${FLTK_CONFIG_PATH}
+# Deprecated: install UseFLTK.cmake with deprecation warnings only
+install (FILES
+  ${CMAKE_CURRENT_BINARY_DIR}/etc/UseFLTK.cmake
+  DESTINATION ${FLTK_CONFIG_PATH}
 )
 
 # generate fltk-config
-set(prefix ${CMAKE_INSTALL_PREFIX})
-set(exec_prefix "\${prefix}")
-set(includedir "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
-set(BINARY_DIR)
-set(libdir "\${exec_prefix}/${CMAKE_INSTALL_LIBDIR}")
-set(srcdir ".")
+set (prefix ${CMAKE_INSTALL_PREFIX})
+set (exec_prefix "\${prefix}")
+set (includedir "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
+set (BINARY_DIR)
+set (libdir "\${exec_prefix}/${CMAKE_INSTALL_LIBDIR}")
+set (srcdir ".")
 
-set(LIBNAME "${libdir}/libfltk.a")
+set (LIBNAME "${libdir}/libfltk.a")
 
 configure_file(
-   "${CMAKE_CURRENT_SOURCE_DIR}/fltk-config.in"
-   "${CMAKE_CURRENT_BINARY_DIR}/bin/fltk-config"
-   @ONLY
+  "${CMAKE_CURRENT_SOURCE_DIR}/fltk-config.in"
+  "${CMAKE_CURRENT_BINARY_DIR}/bin/fltk-config"
+  @ONLY
 )
-if(UNIX)
-   execute_process(COMMAND chmod 755 fltk-config
-      WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/bin"
-   )
-endif(UNIX)
-
-install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/bin/fltk-config
-   DESTINATION ${FLTK_BINDIR}
+
+if (UNIX)
+  execute_process (COMMAND chmod 755 fltk-config
+    WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/bin"
+  )
+endif (UNIX)
+
+install (PROGRAMS
+  ${CMAKE_CURRENT_BINARY_DIR}/bin/fltk-config
+  DESTINATION ${FLTK_BINDIR}
 )
 
-if(UNIX OR MSYS OR (MINGW AND CMAKE_CROSSCOMPILING))
-   macro(INSTALL_MAN FILE LEVEL)
-   install(FILES
+if (UNIX OR MSYS OR (MINGW AND CMAKE_CROSSCOMPILING))
+  macro(INSTALL_MAN FILE LEVEL)
+    install(FILES
       ${CMAKE_CURRENT_SOURCE_DIR}/documentation/src/${FILE}.man
       DESTINATION ${FLTK_MANDIR}/man${LEVEL}
       RENAME ${FILE}.${LEVEL}
-   )
-   endmacro(INSTALL_MAN FILE LEVEL)
+    )
+  endmacro (INSTALL_MAN FILE LEVEL)
 
-   INSTALL_MAN(fluid 1)
-   INSTALL_MAN(fltk-config 1)
-   INSTALL_MAN(fltk 3)
-   INSTALL_MAN(blocks 6)
-   INSTALL_MAN(checkers 6)
-   INSTALL_MAN(sudoku 6)
+  INSTALL_MAN (fluid 1)
+  INSTALL_MAN (fltk-config 1)
+  INSTALL_MAN (fltk 3)
+  INSTALL_MAN (blocks 6)
+  INSTALL_MAN (checkers 6)
+  INSTALL_MAN (sudoku 6)
 
-endif(UNIX OR MSYS OR (MINGW AND CMAKE_CROSSCOMPILING))
+endif (UNIX OR MSYS OR (MINGW AND CMAKE_CROSSCOMPILING))