diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index 5ab3935f6de..0d61f1e213e 100755
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -37,6 +37,10 @@ check_include_file(unistd.h HAVE_UNISTD_H)
 check_include_file(utime.h HAVE_UTIME_H)
 check_include_file(windows.h HAVE_WINDOWS_H)
 
+# library checks
+include(CheckLibraryExists)
+check_library_exists(pthread pthread_create "" HAVE_LIBPTHREAD)
+
 # function checks
 include(CheckSymbolExists)
 check_symbol_exists(getpagesize unistd.h HAVE_GETPAGESIZE)
diff --git a/include/llvm/Config/config.h.cmake b/include/llvm/Config/config.h.cmake
index cabf0f17882..dac1856ea0b 100644
--- a/include/llvm/Config/config.h.cmake
+++ b/include/llvm/Config/config.h.cmake
@@ -194,7 +194,7 @@
 #cmakedefine HAVE_LIBPSAPI ${HAVE_LIBPSAPI}
 
 /* Define to 1 if you have the `pthread' library (-lpthread). */
-#undef HAVE_LIBPTHREAD
+#cmakedefine HAVE_LIBPTHREAD ${HAVE_LIBPTHREAD}
 
 /* Define to 1 if you have the `udis86' library (-ludis86). */
 #undef HAVE_LIBUDIS86