2.5.31: checking for GNU m4

[Hans-Bernhard Broeker]

Hello, flexers,

I think I found a bug in flex-2.5.31's build process:

configure does search for an m4 in the PATH, in a way that prefers GNU m4
over non-GNU m4.  On platforms other than Linux, that will usually not be
the default m4, though, so you'll have to call something else than just
"m4" to get it.  configure should test that the m4 found is actually GNU
m4, since the source uses the GNU m4 only flag '-P'.

In addition to this, the source doesn't make use of configure's findings,
at all. It just does this:

0 main.c 347 filter_create_ext(output_chain,"m4","-P",0);

That "m4" clearly has to be become some macro call whose value is deduced
by configure via config.h, so platforms where GNU m4 is installed as
"gnum4" or similar can use that.

-- 
Hans-Bernhard Broeker (address@hidden)
Even if all the snow were burnt, ashes would remain.