GET_ARG_AFTER(opt, "-isystem");
add_flag(&cppflags_obst, "-isystem");
add_flag(&cppflags_obst, "%s", opt);
+#if defined(linux) || defined(__linux) || defined(__linux__) || defined(__CYGWIN__)
+ } else if (streq(option, "pthread")) {
+ /* set flags for the preprocessor */
+ add_flag(&cppflags_obst, "-D_REENTRANT");
+ /* set flags for the linker */
+ add_flag(&ldflags_obst, "-lpthread");
+#endif
} else if (streq(option, "nostdinc")
|| streq(option, "trigraphs")) {
/* pass these through to the preprocessor */