Makefile: 'make clean' wipe all editor backup files in src/*/

In a similar way to commit 9b173803 ("Make 'make clean' wipe all
object files in src/*/", 2010-04-14), we use a shell glob when
removing editor backup files.

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>

Makefile

@@ -93,7 +93,7 @@ clean:
 	rm -f *.pdb
 	rm -f src/*.o src/*/*.o
 	rm -rf apidocs
-	rm -f *~ src/*~ src/git/*~ src/sha1/*~ src/unix/*~ src/win32/*~
+	rm -f *~ src/*~ src/*/*~
 	@$(MAKE) -C tests -s --no-print-directory clean
 	@$(MAKE) -s --no-print-directory cov-clean