Export __progname even if a -dynamic-list is given.
BSD's progname symbol is defined in crt1.o and linked against main
executables. The libc expects that main executables export progname
symbol via .dynsym sections. In order to handle this case, we scan
undefined symbols in DSOs and exported them by setting Sym->ExportDynamic
But it turned out that setting that variable is not enough to make sure
that symbols are exported in all use cases. If a -dynamic-list option is
given, all symbols not explicitly mentioned in a version script are
hidden by default. That hides __progname symbol. This patch fixes the issue.