Introduce "Modern CMake" in FLTK

This is a big commit and there are too many changes to list them all.
The main changes are:

- rename all CMake build options to 'FLTK_*'
- export library targets with namespace (prefix) 'fltk::'
- standardize shared library target names with suffix '-shared'
- set public build properties on libraries for consumers
- document library names and aliases in README.CMake.txt
- document changes in "Migrating Code from FLTK 1.3 to 1.4"
- partial backwards compatibility for old user projects

Included but not directly related changes:

- fix Windows (Visual Studio) DLL build
- add CMake function fl_debug_target() to show target properties
- don't build test programs if FLTK is a subproject
- internal: reformat CMake code: remove space before '('

Thanks to Matthias and Manolo for their help, testing, and feeback.

1 files changed, 1 insertions, 1 deletions

diff --git a/documentation/Makefile b/documentation/Makefile
index c5450f08c..0b176246b 100644
--- a/documentation/Makefile
+++ b/documentation/Makefile
@@ -140,7 +140,7 @@ uninstall-linux uninstall-osx:
 # Note that Doxyfile.in is shared with CMake to configure these files.
 
 # Note: There's no way to enable the "Driver Documentation" via configure+make,
-#       please use CMake 'OPTION_INCLUDE_DRIVER_DOCUMENTATION' instead.
+#       please use CMake 'FLTK_INCLUDE_DRIVER_DOCS' instead.
 #       Alternatively (if you really need it) edit this Makefile and
 #       replace the two lines below containing "@DRIVER_DOCS@" to read:
 #	    -e's, @DRIVER_DOCS@, DriverDev,' \