improvements to zig build system and unwrap error safety

* zig build system: create standard dynamic library sym links
 * unwrapping an error results in a panic message that contains
   the error name
 * rename error.SysResources to error.SystemResources
 * add std.os.symLink
 * add std.os.deleteFile
47336abae3Andrew Kelley committed on 4/17/2017, 10:47:20 AMparentd16ce67
7 files changedLine totals unavailable