Initial support for gambit-scheme v4.7.0

ports/gambc/build.sh

+#!/bin/bash
+# Copyright (c) 2011 The Native Client Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+ConfigureStep() {
+  export BUILD_DIR=${NACL_PACKAGES_REPOSITORY}/${PACKAGE_DIR}
+  export NACL_CONFIGURE_PATH=./configure
+
+  if [ "${NACL_ARCH}" = "pnacl" ]; then
+    EXTRA_CONFIGURE_FLAGS=""
+    NACLPORTS_CFLAGS+=" -D___NOT_USE_LABEL_VALUES"
+  else
+    # Gambit compiling is extremely slow with this flag under LLVM.
+    EXTRA_CONFIGURE_FLAGS="--enable-single-host"
+  fi
+
+  if [ "${NACL_GLIBC}" != "1" ]; then
+    export LIBS=" -lglibc-compat"
+  else
+    # Gambit decides to use POSIX function only if waitpid exists.
+    export ac_cv_func_waitpid=yes
+  fi
+
+  DefaultConfigureStep --disable-debug ${EXTRA_CONFIGURE_FLAGS}
+}