devtool: add: properly handle separate build directory

When we were adding a recipe for software that would typically be built
in the same directory as the source, we were always using a separate
build directory unless the user explicitly specified not to, leading to
errors for software that doesn't expect to be built that way (such as
Python modules using distutils). Split out the code that makes this
determination automatically from the "devtool modify" and "devtool
upgrade" code and re-use that here so the behaviour is consistent.

(From OE-Core rev: 320585b7ff6340df0b0dbc63f95ed3ca8fc3a993)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/scripts/lib/devtool/__init__.py b/scripts/lib/devtool/__init__.py
index 3ea38028d4..07a3636e9b 100644
--- a/scripts/lib/devtool/__init__.py
+++ b/scripts/lib/devtool/__init__.py
@@ -152,3 +152,21 @@ def check_workspace_recipe(workspace, pn, checksrc=True):
             raise DevtoolError("Source tree %s for recipe %s does not exist" % (srctree, pn))
         if not os.listdir(srctree):
             raise DevtoolError("Source tree %s for recipe %s is empty" % (srctree, pn))
+
+def use_external_build(same_dir, no_same_dir, d):
+    """
+    Determine if we should use B!=S (separate build and source directories) or not
+    """
+    b_is_s = True
+    if no_same_dir:
+        logger.info('Using separate build directory since --no-same-dir specified')
+        b_is_s = False
+    elif same_dir:
+        logger.info('Using source tree as build directory since --same-dir specified')
+    elif bb.data.inherits_class('autotools-brokensep', d):
+        logger.info('Using source tree as build directory since recipe inherits autotools-brokensep')
+    elif d.getVar('B', True) == os.path.abspath(d.getVar('S', True)):
+        logger.info('Using source tree as build directory since that would be the default for this recipe')
+    else:
+        b_is_s = False
+    return b_is_s