+ Partial m4sugar merge from autoconf: m4_shiftn.
+ * data/m4sugar/m4sugar.m4 (m4_shiftn): Faster implementation.
+ (m4_shift2, m4_shift3): New macros.
+ (m4_case, m4_bmatch, m4_bpatsubsts, m4_join): Adjust clients.
+ * data/c.m4 (b4_c_function_def, b4_c_ansi_function_def)
+ (b4_c_ansi_function_decl, b4_c_function_call): Likewise.
+ * data/java.m4 (b4_remove_comma): Likewise.
+