Link with pthreads in core migraphx library since we use threads there (#975)

pthread linking errors on SLES. 

src/CMakeLists.txt

@@ -200,6 +200,9 @@ target_link_libraries(migraphx PRIVATE -ldl)
 
 target_include_directories(migraphx SYSTEM PUBLIC $<BUILD_INTERFACE:${HALF_INCLUDE_DIR}>)
 
+find_package(Threads)
+target_link_libraries(migraphx PUBLIC Threads::Threads)
+
 find_package(msgpack REQUIRED)
 target_link_libraries(migraphx PRIVATE msgpackc-cxx)
 # Make this available to the tests
@@ -237,6 +240,7 @@ rocm_export_targets(
   TARGETS migraphx::migraphx migraphx_all_targets
   NAMESPACE migraphx::
   DEPENDS
+    Threads
     ${PACKAGE_DEPENDS}
 )
  

src/targets/cpu/CMakeLists.txt

@@ -33,8 +33,6 @@ rocm_set_soversion(migraphx_cpu ${MIGRAPHX_SO_VERSION})
 
 set(MIGRAPHX_ENABLE_ZENDNN Off CACHE BOOL "")
 
-find_package(Threads)
-
 if(MIGRAPHX_ENABLE_ZENDNN)
     find_path(ZENDNN_INC_PATH zendnn.hpp)
     find_library(ZENDNN_LIB amdZenDNN)
@@ -53,7 +51,7 @@ if(MIGRAPHX_ENABLE_ZENDNN)
 else()
     target_link_libraries(migraphx_cpu PRIVATE DNNL::dnnl)
 endif()
-target_link_libraries(migraphx_cpu PRIVATE migraphx Threads::Threads)
+target_link_libraries(migraphx_cpu PRIVATE migraphx)
 
 find_package(OpenMP)
 target_link_libraries(migraphx_cpu PUBLIC OpenMP::OpenMP_CXX)