Another POSIX incompatibility

[Eric Blake]

The Austin group just released its first draft of the next revision of POSIX; 
you have to be a member of the Austin group to read it (registration is free).  
In comparing the proposed changes against current POSIX, I found another GNU m4 
bug:

$ echo hi > foo
$ /usr/xpg4/bin/m4 -Dhi=1 foo -Dhi=2 foo
1
2
$ m4 -Dhi=1 foo -Dhi=2 foo
2
2

The proposed POSIX wording adds "the order of the −D and −U options shall be
significant, and options can be interspersed with operands", validating the 
Solaris behavior.  Patch to follow soon (I guess it's a good thing I wasn't 
able to release m4 1.4.8 last weekend, after all).

-- 
Eric Blake