Detect Cygwin, including the MSYS(2) forks

Cygwin's default terminal, mintty, is able to process ANSI sequences
although it's running on Windows. So treat Cygwin as a Unix variant.

Fixes #39.

Author: ylangisc

jansi/src/main/java/org/fusesource/jansi/AnsiConsole.java

@@ -61,7 +61,7 @@ public static OutputStream wrapOutputStream(final OutputStream stream, int filen
         }
 
 		String os = System.getProperty("os.name");
-		if( os.startsWith("Windows") ) {
+		if( os.startsWith("Windows") && !isCygwin() ) {
 
 			// On windows we know the console does not interpret ANSI codes..
 			try {
@@ -75,15 +75,15 @@ public static OutputStream wrapOutputStream(final OutputStream stream, int filen
 			return new AnsiOutputStream(stream);
 		}
 
-		// We must be on some unix variant..
+		// We must be on some Unix variant, including Cygwin or MSYS(2) on Windows...
 		try {
 			// If the jansi.force property is set, then we force to output 
 			// the ansi escapes for piping it into ansi color aware commands (e.g. less -r)
 			boolean forceColored = Boolean.getBoolean("jansi.force");
 			// If we can detect that stdout is not a tty.. then setup
 			// to strip the ANSI sequences..
 			int rc = isatty(fileno);
-			if( !forceColored && rc==0 ) {
+			if( !isCygwin() && !forceColored && rc == 0 ) {
 				return new AnsiOutputStream(stream);
 			}
 
@@ -105,6 +105,11 @@ public void close() throws IOException {
 		};
 	}
 
+	private static boolean isCygwin() {
+		String term = System.getenv("TERM");
+		return term != null && term.equals("xterm");
+	}
+
 	/**
 	 * If the standard out natively supports ANSI escape codes, then this just 
 	 * returns System.out, otherwise it will provide an ANSI aware PrintStream