[PATCH] autotools: Use make clean for builds not supporting B != S

[Richard Purdie <richard.purdie@linuxfoundation.org>]

If the build doesn't support B != S, we can try running "make clean" instead
to try and clean up previous objects if the hash for the task has changed.

This tries to ensure that when variables like ${baselib} change, the changes are
correctly accounted for.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/meta/classes/autotools.bbclass b/meta/classes/autotools.bbclass
index 6b99bdd..bed8a83 100644
--- a/meta/classes/autotools.bbclass
+++ b/meta/classes/autotools.bbclass
@@ -109,7 +109,11 @@ autotools_preconfigure() {
 			else
 				# At least remove the .la files since automake won't automatically
 				# regenerate them even if CFLAGS/LDFLAGS are different
-				cd ${S}; find ${S} -name \*.la -delete
+				cd ${S}
+				if [ -e Makefile -o -e makefile -o -e GNUmakefile ]; then
+					${MAKE} clean
+				fi
+				find ${S} -name \*.la -delete
 			fi
 		fi
 	fi