Simplify resolving symlinks, remove native extension (#1428)

src/configure

@@ -1,49 +1,7 @@
 #!/usr/bin/env bash
+# Warning: this configure script is obsolete and kept only for backwards compatibility.
 set -e
 
 src_dir="${0%/*}"
 
-if [ -z "$CC" ]; then
-  if type -p gcc >/dev/null; then
-    CC=gcc
-  else
-    echo "warning: gcc not found; using CC=cc" >&2
-    CC=cc
-  fi
-fi
-
-if ! type -p "$CC" >/dev/null; then
-  echo "aborted: compiler not found: $CC" >&2
-  exit 1
-fi
-
-case "$(uname -s)" in
-Darwin* )
-  host_os="darwin$(uname -r)"
-  ;;
-FreeBSD* )
-  host_os="freebsd$(uname -r)"
-  ;;
-OpenBSD* )
-  host_os="openbsd$(uname -r)"
-  ;;
-* )
-  host_os="linux-gnu"
-esac
-
-eval "$("$src_dir"/shobj-conf -C "$CC" -o "$host_os")"
-
-sed "
-  s#@CC@#${CC}#
-  s#@CFLAGS@#${CFLAGS}#
-  s#@LOCAL_CFLAGS@#${LOCAL_CFLAGS}#
-  s#@DEFS@#${DEFS}#
-  s#@LOCAL_DEFS@#${LOCAL_DEFS}#
-  s#@SHOBJ_CC@#${SHOBJ_CC}#
-  s#@SHOBJ_CFLAGS@#${SHOBJ_CFLAGS}#
-  s#@SHOBJ_LD@#${SHOBJ_LD}#
-  s#@SHOBJ_LDFLAGS@#${SHOBJ_LDFLAGS}#
-  s#@SHOBJ_XLDFLAGS@#${SHOBJ_XLDFLAGS}#
-  s#@SHOBJ_LIBS@#${SHOBJ_LIBS}#
-  s#@SHOBJ_STATUS@#${SHOBJ_STATUS}#
-" "$src_dir"/Makefile.in > "$src_dir"/Makefile
+cp "$src_dir"/Makefile.in "$src_dir"/Makefile