[fpc-devel] Build failure in Fedora 35 due to glibc 2.34 code hardening

[Florian Klämpfl]

> Am 07.08.2021 um 16:59 schrieb Mattia Verga via fpc-devel <fpc-devel at lists.freepascal.org>:
> 
> Fedora has recently moved to using glibc 2.34. That caused Free Pascal
> Compiler to stop building with the following output:
> 
> /usr/bin/ld:
> /builddir/build/BUILD/fpcbuild-3.2.2/fpcsrc/rtl/units/powerpc64-linux/si_c.o:(.data.n_TC_$SI_C_$$_START_ADDRESSES+0x10):
> undefined reference to `__libc_csu_init'
> /usr/bin/ld:
> /builddir/build/BUILD/fpcbuild-3.2.2/fpcsrc/rtl/units/powerpc64-linux/si_c.o:(.data.n_TC_$SI_C_$$_START_ADDRESSES+0x18):
> undefined reference to `__libc_csu_fini'
> Error: Error while linking
> 
> One of the guys responsible for glibc in Fedora gave this explanation:
> 
>> It's related to startup code hardening in glibc.  In general, it's
> not forward-compatible to call internal glibc functions this way.
>> __libc_csu_init and __libc_csu_fini where never part of any header file.
>> It's not clear to me why fpc needs to replace the startup code.  They
> could supply a C main function and call Pascall code from that.
>   Or
> compile the main program in such a way that it has a compatible
> interface with the C main program.

This is not what we want. We just want to initialize glibc from *our* startup code for various reasons. And if a library is written properly, this must be possible.