Include signal.h depending on HAVE_SIGNAL_H, not depending on __linux__
diff --git a/lib/cpp/test/TSSLSocketInterruptTest.cpp b/lib/cpp/test/TSSLSocketInterruptTest.cpp
index 83fb993..bdaa466 100644
--- a/lib/cpp/test/TSSLSocketInterruptTest.cpp
+++ b/lib/cpp/test/TSSLSocketInterruptTest.cpp
@@ -27,7 +27,7 @@
 #include <memory>
 #include <thrift/transport/TSSLSocket.h>
 #include <thrift/transport/TSSLServerSocket.h>
-#ifdef __linux__
+#ifdef HAVE_SIGNAL_H
 #include <signal.h>
 #endif