diff --git a/Utilities/cmlibarchive/CMakeLists.txt b/Utilities/cmlibarchive/CMakeLists.txt
index 6b13c2fd97..00550e2e99 100644
--- a/Utilities/cmlibarchive/CMakeLists.txt
+++ b/Utilities/cmlibarchive/CMakeLists.txt
@@ -94,6 +94,8 @@ IF(WIN32)
   SET(_WIN32_WINNT ${WINVER})
 ENDIF(WIN32)
 
+set(HAVE_PTHREAD_H 0) # no threads in CMake
+
 IF("${CMAKE_C_PLATFORM_ID}" MATCHES "^(HP-UX)$")
   ADD_DEFINITIONS(-D_XOPEN_SOURCE=500) # Ask wchar.h for mbstate_t
 ENDIF()