RFC: CMAKE - support out of tree builds

[Robert Schuster <thebohemian@gmx.net>]

[-- Attachment #1.1: Type: text/plain, Size: 340 bytes --]

Hi,
I am proposing the attached patch to make it possible to do out-of-tree
builds in OE. Out-of-tree builds should be preferred but I do not want
to look at every recipe if it still works.

OTOH I want to include llvm 2.5 with its new cmake-based build system
which incidentally does *not* permit in-tree builds.

Regards
Robert

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1.2: oe-cmake-outoftree.patch --]
[-- Type: text/x-patch; name="oe-cmake-outoftree.patch", Size: 1106 bytes --]

diff --git a/classes/cmake.bbclass b/classes/cmake.bbclass
index 8fd25cd..7907f94 100644
--- a/classes/cmake.bbclass
+++ b/classes/cmake.bbclass
@@ -3,13 +3,25 @@ DEPENDS += " cmake-native "
 # We want the staging and installing functions from autotools
 inherit autotools
 
+# Use in-tree builds by default but allow this to be changed
+# since some packages do not support them (e.g. llvm 2.5).
 OECMAKE_SOURCEPATH ?= "."
 
+# If declaring this, make sure you also set EXTRA_OEMAKE to
+# "-C ${OECMAKE_BUILDPATH}". So it will run the right makefiles.
+OECMAKE_BUILDPATH ?= ""
+
 cmake_do_configure() {
-     cmake ${OECMAKE_SOURCEPATH} \
-     -DCMAKE_INSTALL_PREFIX:PATH=${prefix} -Wno-dev \
-     -DCMAKE_FIND_ROOT_PATH=${STAGING_DIR_HOST} \
-     ${EXTRA_OECMAKE}
+  if [ ${OECMAKE_BUILDPATH} ]
+  then
+    mkdir ${OECMAKE_BUILDPATH}
+    cd ${OECMAKE_BUILDPATH}
+  fi
+
+  cmake ${OECMAKE_SOURCEPATH} \
+    -DCMAKE_INSTALL_PREFIX:PATH=${prefix} -Wno-dev \
+    -DCMAKE_FIND_ROOT_PATH=${STAGING_DIR_HOST} \
+    ${EXTRA_OECMAKE}
 }
 
 EXPORT_FUNCTIONS do_configure

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 268 bytes --]