CYGWIN provides an implemention of libargp as a separate package:

https://cygwin.com/cgi-bin2/package-grep.cgi?grep=libargp&arch=x86_64

The current CMakeLists.txt already provides the detection of this library for BSD/SOLARIS/OSX, so CYGWIN can be easily added there for support.

Signed-off-by: Carlo Bramini <carlo_bramini@users.sourceforge.net>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>

CMakeLists.txt

@@ -103,9 +103,9 @@ if (WITH_NACL)
     endif (NOT NACL_FOUND)
 endif (WITH_NACL)
 
-if (BSD OR SOLARIS OR OSX)
+if (BSD OR SOLARIS OR OSX OR CYGWIN)
     find_package(Argp)
-endif (BSD OR SOLARIS OR OSX)
+endif (BSD OR SOLARIS OR OSX OR CYGWIN)
 
 # Disable symbol versioning in non UNIX platforms
 if (UNIX)