[lld][MachO] Use a std::string rather than a StringRef for the section name in MachODefinedCustomSectionAtom.
[lld][MachO] Use a std::string rather than a StringRef for the section name in
MachODefinedCustomSectionAtom.

The section names for these atoms are initialized from temporaries (e.g.
segName + "/" + sectName), so we can't use StringRef here.



git-svn-id: f6089bf0e6284f307027cef4f64114ee9ebb0424@251610 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lld,llvm-mirror/lld