Issue
The project I am attempting compile is not in any way complex, and references nothing but the standard library and one self-contained library (everything compiles fine on another system). As indicated by the title, it can't even link against something in the standard library, due to things in there not having been compiled with -fPIC, supposedly. I didn't build it myself, nor do I want to, and reinstalling things with apt didn't seem to resolve the "recompile with -fPIC" issue.
I will say that I think one possible source of the issue is due to gcc-multilib or something being installed earlier, but I think that was purged. I don't know, maybe something was overwritten or a conflict arose. Might not even be related. Any ideas?
Running Ubuntu 18.04
g++ -I inc -I /usr/include/mono-2.0 -MMD -MF dep/Nonsense.d -std=c++17 -O3 -fno-stack-protector -fno-unroll-loops -fomit-frame-pointer -Wno-ignored-optimization-argument -c -o obj/Nonsense.o src/Nonsense.cpp
g++ -I inc -I /usr/include/mono-2.0 -MMD -MF dep/Socket.d -std=c++17 -O3 -fno-stack-protector -fno-unroll-loops -fomit-frame-pointer -Wno-ignored-optimization-argument -c -o obj/Socket.o src/Socket.cpp
g++ -shared -flto -o libNonsense.so obj/Nonsense.o obj/Socket.o -Llib -lenet
/usr/bin/x86_64-linux-gnu-ld: obj/Socket.o: relocation R_X86_64_PC32 against symbol `_ZTISt13runtime_error@@GLIBCXX_3.4' can not be used when making a shared object; recompile with -fPIC
/usr/bin/x86_64-linux-gnu-ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
makefile:22: recipe for target 'libNonsense.so' failed
make: *** [libNonsense.so] Error 1
Solution
As the error message says, you need to recompile with -fPIC. Your current compiler command does not show the -fPIC option:
g++ -I inc -I /usr/include/mono-2.0 -MMD -MF dep/Socket.d -std=c++17 -O3 -fno-stack-protector -fno-unroll-loops -fomit-frame-pointer -Wno-ignored-optimization-argument -c -o obj/Socket.o src/Socket.cpp
Same for -flto by the way—this flag also has to be specified when compiling in order to be effective.
Answered By - Florian Weimer Answer Checked By - Robin (WPSolving Admin)