RFE: archk detect non-PIC code

[Jeff Johnson]

On AMD64, builds of shared objects against archives will fail unless the
archives are built properly. On other platforms it works, although it's
considered a bad idea. archk should be able to detect this situation and report
on it:

gcc -o ./libfontconfig.so.1.0.4~ -shared -Wl,-soname,libfontconfig.so.1
fcatomic.o fcblanks.o fccache.o fccfg.o fccharset.o fcdbg.o fcdefault.o fcdir.o
fcfreetype.o fcfs.o fcinit.o fclang.o fclist.o fcmatch.o fcmatrix.o fcname.o
fcpat.o fcstr.o fcxml.o -L../../exports/lib -lfreetype -lexpat -lc
/usr/bin/ld: ../../exports/lib/libfreetype.a(ftbase.o): relocation R_X86_64_32S
can not be used when making a shared object; recompile with -fPIC