From 7cf0cf7524c20dc12cdb25ab44b90baec6396bbb Mon Sep 17 00:00:00 2001
From: Josh Blum <josh@joshknows.com>
Date: Wed, 4 Jul 2018 11:45:25 -0500
Subject: [PATCH] link with pthreads only when using gcc

Fix from c98be5dd for MSVC which does not require pthreads for boost threading library.
Under gcc -pthread adds support for multithreading with the pthreads library.
---
 lib/CMakeLists.txt | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 4f83f72..dbb175a 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -43,7 +43,11 @@ GR_OSMOSDR_APPEND_SRCS(
     time_spec.cc
 )
 
-list(APPEND Boost_LIBRARIES pthread)
+#-pthread Adds support for multithreading with the pthreads library.
+#This option sets flags for both the preprocessor and linker. (man gcc)
+if(CMAKE_COMPILER_IS_GNUCXX)
+    list(APPEND Boost_LIBRARIES -pthread)
+endif()
 
 GR_OSMOSDR_APPEND_LIBS(
     ${Boost_LIBRARIES}