Re: configure enable/disable gsltest

[Brian Gough <bjg at network-theory dot co dot uk>]

The disable-test option only turns off the compilation part of the
test. It still looks for gsl-config.  I'm not sure why it works that
way, but that's what the option does anyway (it probably needs better
name).

To get make use of the results, try something like

  AM_PATH_GSL(0.6.0,[have_gsl=true],[have_gsl=false])
  AM_CONDITIONAL(HAVE_GSL, test x$have_gsl = xtrue)

and in your Makefile.am

     if HAVE_GSL
     PROGS = app1 app2
     else
     PROGS = app2
     endif
     bin_PROGRAMS = $(PROGS)

That is based on the example in the conditionals chapter in the
automake manual.

Bill Brower writes:
 > another configure/gsl.m4 issue?
 > 
 > configure --disable-gsltest
 > 
 > and
 > 
 > configure --enable-gsltest=no
 > 
 > seem to have the same, incorrect result.
 > Both go ahead and check for gsl-config and the library.
 > Am I correct in assuming these flags are supposed to 
 > prevent the GSL checks from taking place?
 > 
 > Now a related question. Let's say I have an autoconf'ed
 > project called "top" which builds a two applications
 > "app1" and "app2". Say "app1" requires the GSL
 > but "app2" does not. Is there a graceful way to NOT
 > attempt the build of "app1" if someone configures
 > with "--disable-gsltest"? How about if the gsltest
 > check fails? I've read the autoconf/automake
 > manuals but examples seem to be worth much more.
 > 
 > Cheers,
 > Bill
 > --
 > William Brower  MIT Lincoln Laboratory
 > 805.355.1310    KMR Field Site, Kwajalein
 >