Mercury element fails to compile on ubuntu 18.04 with GCC 7.5.0

[jleidel]

Ubuntu 18.04 LTS; x86_64; gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0 (installed from apt)

The mercury element fails to compile from the devel branch. The last commit on mercury was from @jpkenny. The linker appears to not like the existence of __exit symbols in the binary. This may be a configuration issue as the linker complains that the objects are not built with -fPIC.

Note that this works on Ubuntu 21.04 with gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0.

/usr/bin/ld: operating_system/threading/asm/.libs/make_x86_64_sysv_macho_gas.o: relocation R_X86_64_PC32 against undefined symbol `__exit' can not be used when making a shared object; recompile with -fPIC

[jpkenny]

Thanks for the report. In theory libtool should be handling -fPIC, so I'll have to dig into what's going on here.

[jpkenny]

Definitely a bug, but the PIC warning is a red herring. Just needed to fix asm handling in the makefile. PR #1954 should resolve issue.

[jleidel]

fixed upstream