Dear specialists, I tried to install gcc6.4.0 in Fedora28, while something wrong happened as following. In file included from ../.././libgcc/unwind-dw2.c:401:0: ./md-unwind-support.h: In function ‘x86_64_fallback_frame_state’: ./md-unwind-support.h:65:47: error: dereferencing pointer to incomplete type ‘struct ucontex_t’ sc = (struct sigcontext *) (void *) &uc_->uc_mcontext; ^~ And at the end the message is here: make[3]: *** [../.././libgcc/shared-object.mk:14: unwind-dw2.o] Error 1 make[3]: *** Waiting for unfinished jobs.... make[3]: Leaving directory '/home/rx/program/gcc-6.4.0/x86_64-pc-linux-gnu/libgcc' make[2]: *** [Makefile:17378: all-stage1-target-libgcc] Error 2 make[2]: Leaving directory '/home/rx/program/gcc-6.4.0' make[1]: *** [Makefile:23677: stage1-bubble] Error 2 make[1]: Leaving directory '/home/rx/program/gcc-6.4.0' make: *** [Makefile:914: all] Error 2 I have try the previous solution( https://stackoverflow.com/questions/46999900/how-to-compile-gcc-6-4-0-with-gcc-7-2-in-archlinux) , but it still failed. Am I missing something? Thank you! PS: This problem is also posted in stackoverflow( https://stackoverflow.com/questions/52498431/compile-gcc6-4-0-using-gcc8-1-1 ) Best regards! Jianhao