...and the workaround for that issue was to add `--target=x86_64-linux-gnu` which, as I understand it, switches the build into the cross-compiler mode. I think there was some variance in the treatment of that flag in GCC versions 7/10/11... Curiously, `--target=x86_64-pc-linux-gnu` does not help... I am guessing that matches the host... And also, the generated executable bundle only has full names like `x86_64-linux-gnu-c++`, there are no `c++`, `cpp` etc. Can anyone shed some light on this aspect of the build process please? On Thu, Sep 23, 2021 at 6:42 PM Oleg Smolsky <osmolsky@xxxxxxxxxxxx> wrote: > Hello there! I'm trying to setup a GCC 11.2 using --with-sysroot=$sysroot > (into which glibc is already installed). I get far enough to have `xgcc` > executable (which works). The executable itself is configured to get glibc > from sysroot (I did that via LDFLAGS): > > ``` > $ ldd ./gcc/xgcc > linux-vdso.so.1 (0x00007ffec27d7000) > libm.so.6 => /opt/sysroot/usr/lib/libm.so.6 (0x00007fc12463c000) > libc.so.6 => /opt/sysroot/usr/lib/libc.so.6 (0x00007fc124440000) > /opt/sysroot/usr/lib/ld-linux-x86-64.so.2 => > /lib64/ld-linux-x86-64.so.2 (0x00007fc124718000) > ``` > > where > LDFLAGS="-Wl,--dynamic-linker,$sysroot/usr/lib/ld-linux-x86-64.so.2,--rpath,$sysroot/usr/lib" > > Things break a little further down the road when building libgomp: > > checking whether we are cross compiling... configure: error: in > `.../gcc11sr/_obj/x86_64-pc-linux-gnu/libgomp': > configure: error: cannot run C compiled programs. > > The issue here, it seems, is the absence of LDFLAGS that I had passed to > the top-level `configure` script. We can see the compiler invocation in the > log: > > configure:3996: .../gcc11sr/_obj/./gcc/xgcc -B.../gcc11sr/_obj/./gcc/ > -B/opt/gcc-11sr/x86_64-pc-linux-gnu/bin/ > -B/opt/gcc-11sr/x86_64-pc-linux-gnu/lib/ -isystem > /opt/gcc-11sr/x86_64-pc-linux-gnu/include -isystem > /opt/gcc-11sr/x86_64-pc-linux-gnu/sys-include -o conftest -g -O2 > conftest.c >&5 > > The compiler yields a correctly-formed executable when I take that very > command line and add LDFLAGS. > > So, finally my question: is this the right way to build a "sysrooted" GCC? > IIRC this recipe worked in the GCC7 days... > > Thanks in advance, > Oleg. >
