[CLAM] Bug in configure script for CLAM 0.5.7

[Simon Dixon]

The following line in the configure script is wrong:

	if test -f `which fltk-config`

When "which" returns the empty string, "test -f" returns true (!).
It should be:

	if test -f "`which fltk-config`"


- Simon




Test output:
------------
sh-2.05b$ if test -f `` ; then echo yes ; else echo no; fi
yes
sh-2.05b$ if test -f "" ; then echo yes ; else echo no; fi
no
sh-2.05b$ if test -f `which fltk-config` ; then echo yes ; else echo no; fi
yes
sh-2.05b$ if test -f "`which fltk-config`" ; then echo yes ; else echo no; fi
no