diff --git a/yocto-poky/meta/classes/externalsrc.bbclass b/yocto-poky/meta/classes/externalsrc.bbclass
index f7ed66d..da7eb47 100644
--- a/yocto-poky/meta/classes/externalsrc.bbclass
+++ b/yocto-poky/meta/classes/externalsrc.bbclass
@@ -25,6 +25,7 @@
 #
 
 SRCTREECOVEREDTASKS ?= "do_patch do_unpack do_fetch"
+EXTERNALSRC_SYMLINKS ?= "oe-workdir:${WORKDIR} oe-logs:${T}"
 
 python () {
     externalsrc = d.getVar('EXTERNALSRC', True)
@@ -51,7 +52,7 @@
             # Dummy value because the default function can't be called with blank SRC_URI
             d.setVar('SRCPV', '999')
 
-        tasks = filter(lambda k: d.getVarFlag(k, "task"), d.keys())
+        tasks = filter(lambda k: d.getVarFlag(k, "task", True), d.keys())
 
         for task in tasks:
             if task.endswith("_setscene"):
@@ -82,12 +83,72 @@
             bb.build.deltask(task, d)
 
         d.prependVarFlag('do_compile', 'prefuncs', "externalsrc_compile_prefunc ")
+        d.prependVarFlag('do_configure', 'prefuncs', "externalsrc_configure_prefunc ")
 
-        # Ensure compilation happens every time
-        d.setVarFlag('do_compile', 'nostamp', '1')
+        # Force the recipe to be always re-parsed so that the file_checksums
+        # function is run every time
+        d.setVar('BB_DONT_CACHE', '1')
+        d.setVarFlag('do_compile', 'file-checksums', '${@srctree_hash_files(d)}')
+
+        # We don't want the workdir to go away
+        d.appendVar('RM_WORK_EXCLUDE', ' ' + d.getVar('PN', True))
+
+        # If B=S the same builddir is used even for different architectures.
+        # Thus, use a shared CONFIGURESTAMPFILE and STAMP directory so that
+        # change of do_configure task hash is correctly detected and stamps are
+        # invalidated if e.g. MACHINE changes.
+        if d.getVar('S', True) == d.getVar('B', True):
+            configstamp = '${TMPDIR}/work-shared/${PN}/${EXTENDPE}${PV}-${PR}/configure.sstate'
+            d.setVar('CONFIGURESTAMPFILE', configstamp)
+            d.setVar('STAMP', '${STAMPS_DIR}/work-shared/${PN}/${EXTENDPE}${PV}-${PR}')
+}
+
+python externalsrc_configure_prefunc() {
+    # Create desired symlinks
+    symlinks = (d.getVar('EXTERNALSRC_SYMLINKS', True) or '').split()
+    for symlink in symlinks:
+        symsplit = symlink.split(':', 1)
+        lnkfile = os.path.join(d.getVar('S', True), symsplit[0])
+        target = d.expand(symsplit[1])
+        if len(symsplit) > 1:
+            if os.path.islink(lnkfile):
+                # Link already exists, leave it if it points to the right location already
+                if os.readlink(lnkfile) == target:
+                    continue
+                os.unlink(lnkfile)
+            elif os.path.exists(lnkfile):
+                # File/dir exists with same name as link, just leave it alone
+                continue
+            os.symlink(target, lnkfile)
 }
 
 python externalsrc_compile_prefunc() {
     # Make it obvious that this is happening, since forgetting about it could lead to much confusion
     bb.plain('NOTE: %s: compiling from external source tree %s' % (d.getVar('PN', True), d.getVar('EXTERNALSRC', True)))
 }
+
+def srctree_hash_files(d):
+    import shutil
+    import subprocess
+    import tempfile
+
+    s_dir = d.getVar('EXTERNALSRC', True)
+    git_dir = os.path.join(s_dir, '.git')
+    oe_hash_file = os.path.join(git_dir, 'oe-devtool-tree-sha1')
+
+    ret = " "
+    if os.path.exists(git_dir):
+        with tempfile.NamedTemporaryFile(dir=git_dir, prefix='oe-devtool-index') as tmp_index:
+            # Clone index
+            shutil.copy2(os.path.join(git_dir, 'index'), tmp_index.name)
+            # Update our custom index
+            env = os.environ.copy()
+            env['GIT_INDEX_FILE'] = tmp_index.name
+            subprocess.check_output(['git', 'add', '.'], cwd=s_dir, env=env)
+            sha1 = subprocess.check_output(['git', 'write-tree'], cwd=s_dir, env=env)
+        with open(oe_hash_file, 'w') as fobj:
+            fobj.write(sha1)
+        ret = oe_hash_file + ':True'
+    else:
+        ret = d.getVar('EXTERNALSRC', True) + '/*:True'
+    return ret