Bug#925129: ffcall failed to build mips64 R6 version due to Illegal instruction

[Bruno Haible <bruno@clisp.org>]

Hi,

In <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=925129> you reported
a problem with the use of the 'jr $25' instruction on MIPS32R6. Thanks for
this report.

I've changed the code to use the new opcode (previously written as
'jal $0,$25') always, since this opcode is supported since the earliest
MIPS ISAs.

https://git.savannah.gnu.org/gitweb/?p=libffcall.git;a=commitdiff;h=5f801d3d01a079c49c1e84b02ab5a153efd5c428

Bruno