Skipped building if the patch's sha matches the previously written patch's sha.

bin/build-libbitcoind

@@ -6,6 +6,7 @@ depends_dir=$($root_dir/platform/os.sh depends_dir)
 os_dir=$(${root_dir}/platform/os.sh osdir)
 host=$(${root_dir}/platform/os.sh host)
 btc_dir="${root_dir}/libbitcoind"
+ext=$($root_dir/platform/os.sh ext)
 echo "Using BTC directory: ${btc_dir}"
 
 cd "${root_dir}"
@@ -61,6 +62,18 @@ if [ "${BITCOINDJS_ENV}" == "test" ]; then
   options=`cat ${root_dir}/bin/config_options_test.sh`
 fi
 
+patch_file_sha=$(shasum -a 256 "${root_dir}/etc/bitcoin.patch" | awk '{print $1}')
+if [ "${ext}" == "dylib" ]; then
+  last_patch_file_sha=$(cat "${os_dir}"/lib/patch_sha.txt)
+else
+  last_patch_file_sha=$(cat "${os_dir}"/patch_sha.txt)
+fi
+shared_file_built=false
+if [ "${last_patch_file_sha}" == "${patch_file_sha}" ]; then
+  shared_file_built=true
+fi
+
+if [ "${shared_file_built}" = false ]; then
   only_make=false
   if [ -d "${btc_dir}" ]; then
     echo "running compare patch..."
@@ -94,7 +107,7 @@ fi
   set -e
 
   if [ "${only_make}" = false ]; then
-  echo "Removing cloning, patching, and building libbitcoind..."
+    echo "Cloning, patching, and building libbitcoind..."
     get_patch_file
     echo "attempting to checkout tag: ${tag} of bitcoin from github..."
     cd "${root_dir}"
@@ -125,7 +138,6 @@ ${full_options}
   echo 'make V=1'
   make V=1
 
-ext=$($root_dir/platform/os.sh ext)
   echo 'Copying libbitcoind.{so|dylib} to its appropriate location.'
   if test -e "${btc_dir}/src/.libs/libbitcoind.${ext}"; then
     if [ "$ext" = "dylib" ]; then
@@ -139,6 +151,11 @@ if test -e "${btc_dir}/src/.libs/libbitcoind.${ext}"; then
       fi
       cp -P "${btc_dir}"/src/.libs/libbitcoind.so* "${os_dir}/"
     fi
+    echo "Creating the sha marker for the patching in libbitcoind..."
+    echo -n `shasum -a 256 "${root_dir}"/etc/bitcoin.patch | awk '{print $1}'` > "${os_dir}"/patch_sha.txt
+  fi
+  echo 'Build finished successfully.'
+else
+  echo 'Using existing shared library.'
 fi
 
-echo 'Build finished successfully.'