remove unused PkgPrecompileError type (#3858)

src/Types.jl

@@ -20,7 +20,7 @@ using SHA
 
 export UUID, SHA1, VersionRange, VersionSpec,
     PackageSpec, PackageEntry, EnvCache, Context, GitRepo, Context!, Manifest, Project, err_rep,
-    PkgError, pkgerror, PkgPrecompileError,
+    PkgError, pkgerror,
     has_name, has_uuid, is_stdlib, is_or_was_stdlib, stdlib_version, is_unregistered_stdlib, stdlibs, write_env, write_env_usage, parse_toml,
     project_resolve!, project_deps_resolve!, manifest_resolve!, registry_resolve!, stdlib_resolve!, handle_repos_develop!, handle_repos_add!, ensure_resolved,
     registered_name,
@@ -68,17 +68,6 @@ end
 pkgerror(msg::String...) = throw(PkgError(join(msg)))
 Base.showerror(io::IO, err::PkgError) = print(io, err.msg)
 
-#################
-# Pkg Precompile Error #
-#################
-struct PkgPrecompileError <: Exception
-    msg::String
-end
-Base.showerror(io::IO, err::PkgPrecompileError) = print(io, err.msg)
-# This needs a show method to make `julia> err` show nicely
-Base.show(io::IO, err::PkgPrecompileError) = print(io, "PkgPrecompileError: ", err.msg)
-
-
 ###############
 # PackageSpec #
 ###############