gcc: should install PIC version of libiberty

[LionNatsu]

Now libiberty.a is not available for shared objects unless it was built with PIC. GCC always builds two libiberty.a and we should install the PIC one not the plain static one.

root@stable-40001 [ ~ ] # cat demangle.c
#include <stdio.h>
#include <libiberty/demangle.h>

__attribute__((constructor))
void mian() {
    char *prot = cplus_demangle("_ZN9wikipedia7article6formatEv", DMGL_AUTO);
    puts(prot);
}
root@stable-40001 [ ~ ] # gcc -shared -fPIC demangle.c -o test.so
root@stable-40001 [ ~ ] # load-shlib ./test.so
./test.so: undefined symbol: cplus_demangle
root@stable-40001 [ ~ ] ! gcc -shared -fPIC demangle.c -o test.so -liberty
/bin/ld: error: /usr/lib/gcc/x86_64-aosc-linux-gnu/8.3.1/../../../../lib64/libiberty.a(cplus-dem.o): requires dynamic R_X86_64_PC32 reloc against '_sch_istable' which may overflow at runtime; recompile with -fPIC
/bin/ld: error: /usr/lib/gcc/x86_64-aosc-linux-gnu/8.3.1/../../../../lib64/libiberty.a(cp-demangle.o): requires dynamic R_X86_64_PC32 reloc against 'cplus_demangle_builtin_types' which may overflow at runtime; recompile with -fPIC
/bin/ld: error: /usr/lib/gcc/x86_64-aosc-linux-gnu/8.3.1/../../../../lib64/libiberty.a(d-demangle.o): requires dynamic R_X86_64_PC32 reloc against '_sch_istable' which may overflow at runtime; recompile with -fPIC
/bin/ld: error: /usr/lib/gcc/x86_64-aosc-linux-gnu/8.3.1/../../../../lib64/libiberty.a(xmalloc.o): requires dynamic R_X86_64_PC32 reloc against 'environ' which may overflow at runtime; recompile with -fPIC
/bin/ld: error: /usr/lib/gcc/x86_64-aosc-linux-gnu/8.3.1/../../../../lib64/libiberty.a(xexit.o
): requires dynamic R_X86_64_PC32 reloc against '_xexit_cleanup' which may overflow at runtime; recompile with -fPIC
collect2: error: ld returned 1 exit status

FYI, Arch Linux had the same issue and they fixed it:

• issue: https://bugs.archlinux.org/task/40174
• commit: https://git.archlinux.org/svntogit/packages.git/commit/trunk/PKGBUILD?h=packages/gcc&id=e691ba34dd83a6fddcdf6f30c6c8d05752051ef6