python-pycurl: build docstrings to fix rebuilds

On a rebuild base.bbclass will invoke "make clean" to ensure that old build
objects are not used. This will delete docstrings.c and the only way to
re-generate that is with a dedicated setup.py target.

(From OE-Core rev: f5bc0ba35ac531feae2e84bbc4f9d16f861db6c6)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python-pycurl_7.19.5.bb

@@ -29,6 +29,11 @@ export STAGING_LIBDIR
 
 BBCLASSEXTEND = "native"
 
+# Ensure the docstrings are generated as make clean will remove them
+do_compile_prepend() {
+	${STAGING_BINDIR_NATIVE}/${PYTHON_PN}-native/${PYTHON_PN} setup.py docstrings
+}
+
 do_install_append() {
 	rm -rf ${D}${datadir}/share
 }