Allow LDFLAGS to be passed from the environment.
--- configure.orig	2017-10-26 04:00:30.000000000 -0500
+++ configure	2018-02-22 15:15:10.000000000 -0600
@@ -56,7 +56,7 @@
 
 #----------------------------------------------------------------------
 # Initialize all variables here such that nothing can leak in from the
-# environment except for CC and CFLAGS, which we might have passed in.
+# environment except for CC, CFLAGS and LDFLAGS, which we might have passed in.
 #----------------------------------------------------------------------
 
 CC=`printf "all:\\n\\t@echo \\\$(CC)\\n" | make -sf -`
@@ -65,7 +65,7 @@
 CFLAGS="${CFLAGS} -Wwrite-strings -Wno-unused-parameter"
 LDADD=
 CPPFLAGS=
-LDFLAGS=
+LDFLAGS=`printf "all:\\n\\t@echo \\\$(LDFLAGS)\\n" | make -sf -`
 PREFIX="/usr/local"
 BINDIR=
 SBINDIR=