According to Harri Pasanen, the Solaris+gcc test for LINKFORSHARED

needed an adaptation for the latest gcc -- we need to grep stderr as
well as stdout for the magic string BFD.  (Does anybody know what BFD
means?)

configure.in

@@ -565,7 +565,7 @@ then
 		fi;;
 	SunOS/5*) case $CC in
 		  *gcc*)
-		    if $CC -Xlinker -V 2>/dev/null | grep BFD >/dev/null
+		    if $CC -Xlinker -V 2>&1 | grep BFD >/dev/null
 		    then
 			LINKFORSHARED="-Xlinker --export-dynamic"
 		    fi;;