Revamped downloading of gmp files.

Revamped cross-compilation support.

core/c/jbigi/download_gmp.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+
+export GMP_VER=6.0.0
+export GMP_TARVER=${GMP_VER}a
+export GMP_DIR="gmp-$GMP_VER"
+export GMP_TAR="gmp-$GMP_TARVER.tar.bz2"
+
+
+function download_tar
+{
+  GMP_TAR_URL="https://gmplib.org/download/gmp/${GMP_TAR}"
+  if [ $(which wget) ]; then
+    echo "Downloading $GMP_TAR_URL"
+    wget -N --progress=dot $GMP_TAR_URL
+  else
+    echo "ERROR: Cannot find wget." >&2
+    echo >&2
+    echo "Please download $GMP_TAR_URL" >&2
+    echo "manually and rerun this script." >&2
+    exit 1
+  fi
+}
+
+function extract_tar
+{
+  tar -xjf ${GMP_TAR} > /dev/null 2>&1 || (rm -f ${GMP_TAR} && download_tar && extract_tar || exit 1)
+}
+
+if [ ! -d "$GMP_DIR" -a ! -e "$GMP_TAR" ]; then
+  download_tar
+fi
+
+if [ ! -d "$GMP_DIR" ]; then
+  extract_tar
+fi