Support lcms2 in MS-Windows builds

Support lcms2 in MS-Windows builds

* lisp/term/w32-win.el (dynamic-library-alist): Include
association for the lcms2 library.

* src/lcms.c [WINDOWSNT]: Include windows.h and w32.h.  Use
DEF_DLL_FN to define pointers to dynamically loaded lcms2
functions.
(cmsCIE2000DeltaE, cmsCIECAM02Init, cmsCIECAM02Forward)
(cmsCIECAM02Done): New macros.
(init_lcms_functions, Flcms2_available_p): New functions.
(Flcms_cie_de2000, Flcms_cam02_ucs) [WINDOWSNT]: Call
init_lcms_functions.
(syms_of_lcms2): Defsubr lcms2-available-p.
* src/w32fns.c (syms_of_w32fns): DEFSYM Qlcms2.

* configure.ac: Include lcms2 in the final report and in
emacs_config_features.

* nt/INSTALL:
* nt/INSTALL.W64: Update with the information about lcms2 library.