From “Notes to chapter 32″ from James E. Talmage’s “Jesus The Christ”:
5. "This Generation." -- Consult any reliable unabridged dictionary of the English language for evidence of the fact that the term "generation," as connoting a period of time, has many meanings, among which are "race, kind, class." The term is not confined to a body of people living at one time. Fausett's Bible Cyclopedia, Critical and Expository, after citing many meanings attached to the word, says: "In Matthew 24:34 `this generation shall not pass (viz. the Jewish race, of which the generation in Christ's days was a sample in character: compare Christ's address to the "generation," 23:35, 36, in proof that "generation" means at times the whole Jewish race) till all these things be fulfilled' -- a prophecy that the Jews shall be a distinct people still when He shall come again."
I believe this also applies to what is said in D&C 84:4-5:
4) Verily this is the word of the Lord, that the city New Jerusalem shall be built by the gathering of the saints, beginning at this place, even the place of the temple, which temple shall be reared in this generation.
5) For verily this generation shall not all pass away until an house shall be built unto the Lord, and a cloud shall rest upon it, which cloud shall be even the glory of the Lord, which shall fill the house.”
It does say “reared” which I’m out of time to study further but still need to.