configure: remove check for libresolve

'strncasecmp' was once provided by libresolv (no trailing e) for SunOS,
but this check is broken and most likely adds nothing useful. Removing
now.

Reported-by: Irfan Adilovic

Discussed in #770

configure.ac

@@ -851,17 +851,6 @@ if test "$HAVE_GETHOSTBYNAME" != "1"; then
   AC_MSG_ERROR([couldn't find libraries for gethostbyname()])
 fi
 
-dnl resolve lib?
-AC_CHECK_FUNC(strcasecmp, , [ AC_CHECK_LIB(resolve, strcasecmp) ])
-
-if test "$ac_cv_lib_resolve_strcasecmp" = "$ac_cv_func_strcasecmp"; then
-  AC_CHECK_LIB(resolve, strcasecmp,
-              [LIBS="-lresolve $LIBS"],
-               ,
-               -lnsl)
-fi
-ac_cv_func_strcasecmp="no"
-
 CURL_CHECK_LIBS_CONNECT
 
 CURL_NETWORK_LIBS=$LIBS