Fix ldd for PIE binaries after rtld stopped accepting binaries for dlopen.

[kib]

Summary

ldd proclaims ET_DYN objects as shared libraries and tries to dlopen(RTLD_TRACE) them to get dependencies. Since PIE binaries are ET_DYN | DF_1_PIE, refusal to dlopen such binaries breaks ldd.

Fix it by reading and parsing dynamic segment looking for DF_FLAG_1 and taking DF_1_PIE into account when deciding between binary and library.

Reported by: Dewayne Geraghty <[e-mail]>

[markj]

usr.bin/ldd/ldd.c

377

Why bother to do this work if e_type == ET_EXEC?

[kib]

Only parse dynamic for ET_DYN.