Merge bitcoin#21911: build: add configure~ to .gitignore

bc45388 build: add *~ to .gitignore (Sjors Provoost)

Pull request description:

  The file `configure~` recently started appearing for me on macOS (11.3.1) whenever configure is (re)run.

ACKs for top commit:
  hebasto:
    ACK bc45388, tested on Linux Mint 20.1 with different build scenarios including cross-compiling for Windows and macOS.

Tree-SHA512: 830c7baf392ff6d66250a79c6ed0a98dac3daaace54a6d2e7940b9a72e3bac79ab44bbecd7642c931fde8a446654e2260d6afdecc679a1743fae6ec5eeda79f1

Author: laanwj

.gitignore

@@ -61,7 +61,7 @@ src/qt/bitcoin-qt.includes
 .dirstamp
 .libs
 .*.swp
-*.*~*
+*~
 *.bak
 *.rej
 *.orig