Use "$(MKDIR_P) sys", not race-prone "test -d sys || mkdir sys". * modules/sys_stat (Makefile.am): Use "$(MKDIR_P) sys", rather than the race-prone "test -d sys || mkdir sys". (configure.ac): Use AC_PROG_MKDIR_P. * modules/sys_select: Likewise. * modules/sys_socket: Likewise. * modules/sys_time: Likewise.