Index: waf-utils.eclass
===================================================================
RCS file: /var/cvsroot/gentoo-x86/eclass/waf-utils.eclass,v
retrieving revision 1.5
diff -u -b -B -r1.5 waf-utils.eclass
--- waf-utils.eclass	1 Mar 2011 23:02:08 -0000	1.5
+++ waf-utils.eclass	14 May 2011 19:47:46 -0000
@@ -24,6 +24,59 @@
 	*) die "EAPI=${EAPI} is not supported" ;;
 esac
 
+# @FUNCTION: waf-utils_waflibdir
+# @USAGE: [<waf-binary>]
+# @DESCRIPTION:
+# Echoes the absolute path to the directory containing the waf-based
+# project's waflib python module. Ensures that the waflib shipped with a
+# project is unpacked if it isn't already. This waflib may be safely
+# patched because waf-lite will not touch the waflib directory if it
+# already exists. Uses the waf binary specified in WAF_BINARY.
+#
+# @EXAMPLE
+# The simplest case, for a monolithic compilation:
+#
+# @CODE
+# pushd "$(waf-utils_waflibdir)" || die "Unable to patch waflib"
+# epatch "${FILESDIR}"/${P}-waf-fix.patch
+# popd
+# @CODE
+#
+# Note that if you are using the python eclass and installating python
+# modules, you must either call python_set_active_version or call
+# waf-utils_waflibdir() from within a function run by
+# python_execute(). This is because waf uses a different directory for
+# waflib when using python3 than when using python2.
+#
+# @CODE
+# SUPPORT_PYTHON_ABIS=1
+# inherit eutils python waf-utils
+#
+# # Always use the waf associated with the current python ABI.
+# WAF_BINARY=./waf
+#
+# src_prepare() {
+# 	python_copy_sources
+#
+# 	myprepare() {
+# 		epatch "${FILESDIR}"/${P}-sourcecode-fix.patch
+#
+# 		pushd "$(waf-utils_waflibdir)" || die "Unable to patch waflib"
+# 		epatch "${FILESDIR}"/${P}-waf-fix.patch
+# 		popd
+# 	}
+# 	python_execute_function -s myprepare
+# }
+# @CODE
+waf-utils_waflibdir() {
+	debug-print-function ${FUNCNAME} "$@"
+
+	: ${WAF_BINARY:="${S}/waf"}
+
+	python -c "import imp, sys; sys.argv[0] = '${WAF_BINARY}'; waflite = imp.load_source('waflite', '${WAF_BINARY}'); print(waflite.find_lib());" \
+		|| die "Unable to locate or unpack waflib module from the waf script at ${WAF_BINARY}"
+}
+
 # @FUNCTION: waf-utils_src_configure
 # @DESCRIPTION:
 # General function for configuring with waf.