Hi Mathieu, Mathieu Othacehe <m.othac...@gmail.com> skribis:
> On master, when building qemu, this is the gcc include path (obtained > with "gcc -v -x c -E /dev/null"): > > /gnu/store/adm2cx3ayabn1sp84nnjsk0672m800ip-flex-2.6.4/include > /gnu/store/l86azr7r3p5631wj3kk329jl1y1mpjgy-bzip2-1.0.6/include > ... > > /gnu/store/2plcy91lypnbbysb18ymnhaw3zwk8pg1-gcc-7.4.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.4.0/include > [1] > > /gnu/store/2plcy91lypnbbysb18ymnhaw3zwk8pg1-gcc-7.4.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.4.0/include-fixed > /gnu/store/ahqgl4h89xqj695lgqvsaf6zh2nhy4pj-glibc-2.29/include [2] > > > We see that glibc comes last. So when building a program with "gcc > -ffreestanding -m16", the first <stdint.h> header picked is the one from > gcc (marked [1] above). This header contains: > > #ifndef _GCC_WRAP_STDINT_H > #if __STDC_HOSTED__ <-- Set to 0 because of -ffreestanding option. > # if defined __cplusplus && __cplusplus >= 201103L > # undef __STDC_LIMIT_MACROS > # define __STDC_LIMIT_MACROS > # undef __STDC_CONSTANT_MACROS > # define __STDC_CONSTANT_MACROS > # endif > # include_next <stdint.h> > #else > # include "stdint-gcc.h" <-- This one gets included. > #endif > #define _GCC_WRAP_STDINT_H > #endif > > > So the <stdint.h> from glibc (marked [2] above) is neved included. And > that's good because this header would try to include <gnu/stubs-32.h> > that our glibc does not provide. [...] > Now, what's happening on core-updates? Because of CPATH -> > C_INCLUDE_PATH transition, we have a different behaviour. The same > command as above states: > > ignoring duplicate directory > "/gnu/store/jsjsczgr8xdnbdminl7lm2v56b7dq7lq-glibc-2.31/include" > ... > /gnu/store/kyypmcn2miyzllqqmcx28gvj89qnvhpi-flex-2.6.4/include > ... > /gnu/store/jsjsczgr8xdnbdminl7lm2v56b7dq7lq-glibc-2.31/include [1] > ... > > /gnu/store/wl7zanqf0s9bfppggmv8qxqan71fjfw8-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/include > [2] > > /gnu/store/wl7zanqf0s9bfppggmv8qxqan71fjfw8-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/include-fixed > > The glibc ignored seems to be the hardcoded one. The one from the > C_INCLUDE_PATH is kept. So the <stdint.h> included is the one from glibc > (marked [1] above), which triggers <gnu/stubs-32.h> inclusion and makes > build fail. Woow, thanks for the analysis. It’s a bug on ‘core-updates’ that GCC’s headers come after libc’s. This is what should be fixed IMO. So is it expected that C_INCLUDE_PATH comes before the hard-coded GCC include directory? How can we work around that? Thanks! Ludo’.
