port should not complain about +universal, CFLAGS/LDFLAGS, configure.universal_cflags-append/configure.universal_ldflags-append

[Ryan Schmidt]

When installing gettext +universal, port warns me that it might not  
work because the port already overrides CFLAGS or LDFLAGS:

$ sudo port install gettext +universal
Warning: This port already overrides CFLAGS or LDFLAGS. The universal  
variant may break it.
--->  Extracting gettext
--->  Applying patches to gettext
--->  Configuring gettext
--->  Building gettext with target all
--->  Staging gettext into destroot
--->  Installing gettext 0.16.1_0+universal
--->  Activating gettext 0.16.1_0+universal
$

However, this is not a problem here because the gettext port deals  
with the situation:

if {[llength [info commands configure.universal_ldflags-append]] > 0} {
	configure.universal_ldflags-append -L$prefix/lib
	configure.universal_cflags-append -I$prefix/include -no-cpp-precomp
} else {
	variant universal {
		return -code error "You need to be running MacPorts 1.4.0 or higher  
to \
		use this variant (universal)."
	}
}

port should not print that warning if configure.universal_cflags- 
append or .universal_ldflags-append are used.