On 09/03/17 01:21, Peter Maydell wrote: > On 8 March 2017 at 13:49, Alexey Kardashevskiy <a...@ozlabs.ru> wrote: >> After 6e85fce0225f "dtc: Update requirement to v1.4.2" QEMU stopped >> compiling in CentOS7: >> >> In file included from /home/aik/p/qemu/dtc/libfdt/libfdt.h:54:0, >> from /home/aik/p/qemu/device_tree.c:30: >> /home/aik/p/qemu/dtc/libfdt/libfdt_env.h:64:0: error: "__bitwise" redefined >> [-Werror] >> #define __bitwise >> ^ >> In file included from /usr/include/asm/ptrace.h:27:0, >> from /usr/include/asm/sigcontext.h:11, >> from /usr/include/bits/sigcontext.h:27, >> from /usr/include/signal.h:340, >> from /home/aik/p/qemu/include/qemu/osdep.h:86, >> from /home/aik/p/qemu/device_tree.c:14: >> /usr/include/linux/types.h:21:0: note: this is the location of the previous >> definition >> #define __bitwise __bitwise__ >> ^ >> cc1: all warnings being treated as errors >> make: *** [device_tree.o] Error 1 >> make: *** Waiting for unfinished jobs.... >> >> The reason is that CentOS7 comes with libfdt 1.4.0 so QEMU tries using >> the internal one which does not compile as CentOS7 comes with gcc v4.8.5 >> which reports warnings which it would not if the OS's libfdt was used >> (libfdt_env.h has not changed between 1.4.0 and 1.4.2). >> >> gcc 6.2.0 from Ubuntu v16.10 handles this fine. >> >> This replaces -I with -isystem to suppress the warning (which turns >> to an error because of -Werror). > > Thanks for the bug report. I think it would be cleaner to fix this
Agree. > by fixing the problem upstream in libfdt and then moving our > submodule forward to the fixed version. (libfdt should not be > defining __ prefixed symbols as these are reserved for the > system.) Also agree, regardless my proposal, libfdt should be fixed. However v2.9 won't compile on CentOS7 (and I suppose on RHEL7) which is a bit annoying. And having "-isystem" makes some sense as these headers are normally system ones and I'd think they should be treated the same way (i.e. path should be included via -isystem vs. -I). -- Alexey
