syscall: don't build libcall_bsd.go on solaris

This new file was based on master sources that are built for *BSD
but not Solaris

Change-Id: Ie170daa4c572e112fe332cc6505eff974f01ec69
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/266017
Trust: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
diff --git a/libgo/go/syscall/libcall_bsd.go b/libgo/go/syscall/libcall_bsd.go
index f13d3bc..1dd957c 100644
--- a/libgo/go/syscall/libcall_bsd.go
+++ b/libgo/go/syscall/libcall_bsd.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd netbsd openbsd solaris
+// +build darwin dragonfly freebsd netbsd openbsd
 
 // BSD library calls.