sys/stropts.h has gone from glibc 04 March 2020, 02:45:47 https://sourceware.org/ml/libc-alpha/2019-08/msg00029.htmlIt provided isastream and I_PUSH among other things. Looking if there was some alternative header providing those I saw this - xtrans is a build dep of libice./usr/include$ ag sys/stroptsX11/Xtrans/Xtranslcl.c84:# include <sys/stropts.h>valgrind/vki/vki-solaris.h1232:#include <sys/stropts.h>/usr/include$ ag isastreamX11/Xtrans/Xtranslcl.c682: extern int isastream(int);721: if (isastream(fd) <= 0) {/usr/include$ ag I_PUSHX11/Xtrans/Xtranslcl.c793: if( ioctl(pipefd[0], I_PUSH, "connld") != 0) {794: prmsg(1, "NAMEDOpenPipe: ioctl(I_PUSH,\"connld\") failed, errno=%d\n",errno);valgrind/vki/vki-solaris.h1237:#define VKI_I_PUSH I_PUSHThere is also still a stropts.h man page.