Fix "fully support ... own shared libraries" (#1238)

- If shared libraries are built, then fluid, fltk-options, and the
  "games" are linked against the shared FLTK libraries. On some
  platforms the static and the shared versions of fluid and
  fltk-options are built. The games are only built if
  FLTK_BUILD_TEST is enabled.

- The CMake 'install' target now installs the games (if built)
  and their man pages on all platforms (no matter if that is
  useful, for instance on Windows).

- On macOS 'CMAKE_INSTALL_RPATH' is set so *installed* programs
  automatically find their shared FLTK libraries. The "shared"
  versions of fluid and fltk-options got their own '.plist' files.
  This works for both the executables themselves as well as those
  included in bundles. There may be more to do on the macOS platform.

2 files changed, 110 insertions, 48 deletions

diff --git a/fltk-options/CMakeLists.txt b/fltk-options/CMakeLists.txt
index 912832839..3f7b1436e 100644
--- a/fltk-options/CMakeLists.txt
+++ b/fltk-options/CMakeLists.txt
@@ -1,7 +1,7 @@
 #
 # CMakeLists.txt to build fltk-options for the FLTK project using CMake (www.cmake.org)
 #
-# Copyright 2023-2024 by Bill Spitzak and others.
+# Copyright 2023-2025 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
@@ -15,46 +15,95 @@
 #
 
 # Targets that will be built: fltk-options and fltk-options-cmd (Windows)
-set(TARGETS fltk-options)
+set(TARGETS "")
 
 if(APPLE AND NOT FLTK_BACKEND_X11)
-
-  # macOS
-
+  set(BACKEND_APPLE TRUE)
   set(ICON_NAME fltk-options.icns)
   set(ICON_PATH "${CMAKE_CURRENT_SOURCE_DIR}/icons/${ICON_NAME}")
-  add_executable(fltk-options MACOSX_BUNDLE fltk-options.cxx ${ICON_PATH})
+  list(APPEND SOURCES ${ICON_PATH})
+else()
+  set(BACKEND_APPLE FALSE)
+  set(ICON_NAME "")
+  set(ICON_PATH "")
+endif()
 
-  # create macOS bundle wrapper script
+# This macro is used to avoid duplicate code to create executable programs.
+# This must be a macro because it changes at least one global variable: TARGETS.
+# This macro also uses some (local) variables defined above.
+# In the future this might be converted to a function to avoid side effects.
 
-  set(WRAPPER "${EXECUTABLE_OUTPUT_PATH}/${CMAKE_CFG_INTDIR}/fltk-options")
-  add_custom_command(
-    TARGET fltk-options POST_BUILD
-    COMMAND cp ${CMAKE_CURRENT_SOURCE_DIR}/../CMake/macOS-bundle-wrapper.in ${WRAPPER}
-    COMMAND chmod u+x,g+x,o+x ${WRAPPER}
-    BYPRODUCTS ${WRAPPER}
-    VERBATIM
-  )
-  unset(WRAPPER)
+macro(make_target TARGET GUI SOURCES LIBS EXPORT_NAME)
 
-else()
+  if(ICON_PATH)
+    list(APPEND SOURCES ${ICON_PATH}) # macOS only
+  endif()
 
-  # Option WIN32 builds a Windows GUI program, ignored on other platforms
-  add_executable(fltk-options WIN32 fltk-options.cxx)
+  # message(STATUS "[fltk-options] make_target ${TARGET} ${GUI} ${SOURCES} ${LIBS} ${EXPORT_NAME}")
 
-endif()
+  # Options WIN32 and MACOSX_BUNDLE build a Windows GUI program or macOS bundle,
+  # respectively. Both options are ignored on other platforms.
 
-target_link_libraries(fltk-options PRIVATE fltk::fltk)
-set_target_properties(fltk-options PROPERTIES EXPORT_NAME options)
+  if(${GUI})
+    add_executable(${TARGET} WIN32 MACOSX_BUNDLE ${SOURCES})
+  else()
+    add_executable(${TARGET} ${SOURCES})
+  endif(${GUI})
+
+  list(APPEND TARGETS ${TARGET})
+
+  if(BACKEND_APPLE)
+
+    # set bundle properties
+    set_target_properties(${TARGET} PROPERTIES MACOSX_BUNDLE_INFO_PLIST "${CMAKE_CURRENT_SOURCE_DIR}/${TARGET}.plist")
+    set_target_properties(${TARGET} PROPERTIES MACOSX_BUNDLE_ICON_FILE ${ICON_NAME})
+    set_target_properties(${TARGET} PROPERTIES XCODE_ATTRIBUTE_PRODUCT_BUNDLE_IDENTIFIER "org.fltk.${TARGET}")
+
+    # install command line tool
+    install(PROGRAMS $<TARGET_FILE:${TARGET}>
+            DESTINATION ${FLTK_BINDIR})
+
+    # create macOS bundle wrapper script
+
+    set(WRAPPER "${EXECUTABLE_OUTPUT_PATH}/${CMAKE_CFG_INTDIR}/${TARGET}")
+    add_custom_command(
+      TARGET ${TARGET} POST_BUILD
+      COMMAND cp ${FLTK_SOURCE_DIR}/CMake/macOS-bundle-wrapper.in ${WRAPPER}
+      COMMAND chmod u+x,g+x,o+x ${WRAPPER}
+      BYPRODUCTS ${WRAPPER}
+      VERBATIM
+    )
+    unset(WRAPPER)
+
+  endif(BACKEND_APPLE)
+
+  target_link_libraries(${TARGET} PRIVATE ${LIBS})
+  set_target_properties(${TARGET} PROPERTIES EXPORT_NAME ${EXPORT_NAME})
+
+endmacro(make_target TARGET GUI LIBS EXPORT_NAME)
+
+set(SOURCES fltk-options.cxx)
+
+make_target(fltk-options TRUE "${SOURCES}" fltk::fltk options)
 
 # Add the console app (Windows only)
 # This is done for all Windows targets, even if cross-compiling.
 
 if(WIN32)
-  list(APPEND TARGETS fltk-options-cmd)
-  add_executable(fltk-options-cmd fltk-options.cxx)
-  target_link_libraries(fltk-options-cmd PRIVATE fltk::fltk)
-  set_target_properties(fltk-options-cmd PROPERTIES EXPORT_NAME options-cmd)
+  make_target(fltk-options-cmd FALSE "${SOURCES}" fltk::fltk options-cmd)
+endif()
+
+# Add the "shared" executable (linked against the shared FLTK libs).
+# Note 1: only the GUI version is built as "shared" executable.
+# Note 2: For MSVC we need the special object library 'call_main'.
+
+if(FLTK_BUILD_SHARED_LIBS)
+  if(MSVC)
+    set(libs fltk::fltk-shared call_main)
+  else()
+    set(libs fltk::fltk-shared)
+  endif()
+  make_target(fltk-options-shared TRUE "${SOURCES}" "${libs}" options-shared)
 endif()
 
 # Create aliases for all executables,
@@ -68,29 +117,8 @@ endforeach()
 
 # Install fltk-options GUI and commandline tool
 
-if(APPLE AND NOT FLTK_BACKEND_X11)
-
-  # On macOS, fltk-options will be installed twice:
-  # - The bundled version goes into the destination folder ${FLTK_BINDIR}.
-  # - The binary without bundle goes into ${FLTK_BINDIR} as well.
-  # These folders are relative to the install prefix, usually 'bin'.
-  # The command line tool is the same executable as the one included in the bundle.
-  # Note:
-  #   Both the bundle and the commandline tool are currently installed side by side.
-  #   This may be changed in the future.
-
-  # set bundle properties
-  set_target_properties(fltk-options PROPERTIES MACOSX_BUNDLE_INFO_PLIST "${CMAKE_CURRENT_SOURCE_DIR}/fltk-options.plist")
-  set_target_properties(fltk-options PROPERTIES MACOSX_BUNDLE_ICON_FILE ${ICON_NAME})
-  set_target_properties(fltk-options PROPERTIES XCODE_ATTRIBUTE_PRODUCT_BUNDLE_IDENTIFIER "org.fltk.fltk-options")
-
-  # install command line tool
-  install(PROGRAMS $<TARGET_FILE:fltk-options>
-          DESTINATION ${FLTK_BINDIR})
-
-endif(APPLE AND NOT FLTK_BACKEND_X11)
-
 # Install the GUI and (on Windows only) the commandline tool 'fltk-options-cmd'
+# message(STATUS "fltk-options: INSTALL TARGETS: ${TARGETS}")
 
 install(TARGETS ${TARGETS}
         EXPORT  FLTK-Targets
diff --git a/fltk-options/fltk-options-shared.plist b/fltk-options/fltk-options-shared.plist
new file mode 100644
index 000000000..6c763f42e
--- /dev/null
+++ b/fltk-options/fltk-options-shared.plist
@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleExecutable</key>
+	<string>fltk-options-shared</string>
+	<key>CFBundleIdentifier</key>
+	<string>org.fltk.fltk-options</string>
+	<key>CFBundleVersion</key>
+	<string>1.5.0</string>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>English</string>
+	<key>NSHumanReadableCopyright</key>
+	<string>Copyright 2023-2025 by Bill Spitzak and others</string>
+	<key>CFAppleHelpAnchor</key>
+	<string>help</string>
+	<key>CFBundleName</key>
+	<string>fltk-options</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleSignature</key>
+	<string>FLOP</string>
+	<key>CFBundleIconFile</key>
+	<string>fltk-options.icns</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.5.0</string>
+	<key>CFBundleGetInfoString</key>
+	<string>1.5.0, Copyright 2023-2025 by Bill Spitzak and others</string>
+	<key>NSHighResolutionCapable</key>
+	<true/>
+</dict>
+</plist>