Added implementation of function "IsTerminal" for Solaris
diff --git a/terminal_solaris.go b/terminal_solaris.go
new file mode 100644
index 0000000..3e70bf7
--- /dev/null
+++ b/terminal_solaris.go
@@ -0,0 +1,15 @@
+// +build solaris
+
+package logrus
+
+import (
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+// IsTerminal returns true if the given file descriptor is a terminal.
+func IsTerminal() bool {
+	_, err := unix.IoctlGetTermios(int(os.Stdout.Fd()), unix.TCGETA)
+	return err == nil
+}