backup of useful relinking script, in case GitHub disappears

Builds/MacOSX/make_portable.sh

@@ -0,0 +1,93 @@
+#!/usr/bin/env bash
+
+# Example input:
+# ./make_portable.sh mycoolbinary
+# where mycoolbinary is a mach-o object file
+# (for example an executable binary or a .dylib)
+#
+# this script rewrites your file's every environment-specific
+# dynamic link (recursively!)
+# such that they point to local .dylibs.
+# these .dylibs are then copied to a folder lib, next to your binary
+#
+# by "environment-specific" I mean any link to a .dylib under /usr/local
+
+set -o pipefail
+
+error() {
+  local parent_lineno="$1"
+  local message="$2"
+  local code="${3:-1}"
+  if [[ -n "$message" ]] ; then
+    echo "Error on or near line ${parent_lineno}: ${message}; exiting with status ${code}"
+  else
+    echo "Error on or near line ${parent_lineno}; exiting with status ${code}"
+  fi
+  exit "${code}"
+}
+trap 'error ${LINENO}' ERR
+
+BINARY="$1"
+BINARYDIR=$(dirname "$BINARY")
+LIBREL="lib"
+LIB="$BINARYDIR/$LIBREL"
+
+# make a lib folder
+mkdir -p "$LIB"
+
+# find every LC_LOAD_DYLIB command in the obj file
+# filter to just loads under /usr/local
+# print the absolute path of each such dylib
+get_env_specific_direct_dependencies () {
+	# otool -L shows us every LC_LOAD_DYLIB plus LC_ID_DYLIB
+	# otool -D shows us just LC_ID_DYLIB
+	ALL_DYLIBS=$(otool -L "$1" | awk 'NR>1')
+	DYLIB_ID=$(otool -D "$1" | awk 'NR>1')
+	if [ -z "$DYLIB_ID" ]; then
+		DIRECT_DEPS="$ALL_DYLIBS"
+	else
+		DIRECT_DEPS=$(echo "$ALL_DYLIBS" | grep -v "$DYLIB_ID")
+	fi
+	echo "$DIRECT_DEPS" \
+	| awk '/\/usr\/local\//,/.dylib/ {print $1}'
+}
+
+# lookup LC_LOAD_DYLIB commands in an obj file,
+# then follow those loads and ask the same of each
+# of its dylibs, recursively
+get_env_specific_dependencies_recursive () {
+	while read -r obj; do
+		[ -z "$obj" ] && continue
+		echo "$obj"
+		get_env_specific_dependencies_recursive "$obj"
+	done < <(get_env_specific_direct_dependencies "$1")
+}
+
+DEP_PATHS=$(get_env_specific_dependencies_recursive "$BINARY")
+
+mkdir -p "$LIB"
+echo "$DEP_PATHS" \
+| xargs -n 1 -I'{}' cp {} "$LIB/"
+
+chmod +w "$LIB"/*.dylib
+
+while read -r obj; do
+	[ -z "$obj" ] && continue
+	OBJ_LEAF_NAME=$(echo "$obj" | awk -F'/' '{print $NF}')
+	# rewrite the install name of this obj file. completely optional.
+	# provides good default for future people who link to it.
+	install_name_tool -id "@rpath/$OBJ_LEAF_NAME" "$obj"
+
+	# iterate over every LC_LOAD_DYLIB command in the objfile
+	while read -r load; do
+		[ -z "$load" ] && continue
+		LOAD_LEAF_NAME=$(echo "$load" | awk -F'/' '{print $NF}')
+		# rewrite a LC_LOAD_DYLIB command in this obj file
+		# to point relative to @rpath
+		install_name_tool -change "$load" "@rpath/$LOAD_LEAF_NAME" "$obj"
+	done < <(get_env_specific_direct_dependencies "$obj")
+done < <(cat <(echo "$BINARY") <(echo "$DEP_PATHS" | awk -F'/' -v l="$LIB" -v OFS='/' '{print l,$NF}'))
+
+# define in our binary what it should expand the
+# runtime search path @rpath to
+install_name_tool -add_rpath "@loader_path/$LIBREL" "$BINARY"