patch 9.1.1081: has('bsd') is true for GNU/Hurd

Problem:  has('bsd') is true for GNU/Hurd
Solution: exclude GNU/Hurd from BSD feature flag
          (Zhaoming Luo)

GNU/Hurd, like Mac OS X, is a BSD-based system. It should exclude
has('bsd') feature just like what Mac OS X does. The __GNU__ pre-defined
macro indicates it's compiled for GNU/Hurd.

closes: #16580

Signed-off-by: Zhaoming Luo <zhmingluo@163.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 69b6a4f..5592471 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -6425,7 +6425,7 @@
 #endif
 		},
 	{"bsd",
-#if defined(BSD) && !defined(MACOS_X)
+#if defined(BSD) && !defined(MACOS_X) && !defined(__GNU__)
 		1
 #else
 		0
@@ -6438,6 +6438,13 @@
 		0
 #endif
 		},
+	{"hurd",
+#ifdef __GNU__
+		1
+#else
+		0
+#endif
+		},
 	{"linux",
 #ifdef __linux__
 		1