toolchain: have check_glibc to search deeper for ld-linux

ld-linux*.so may not be present in lib/ directory, it could be
in lib32 and/or lib64 only. But check_glibc reports
"Incorrect selection of the C library" in this case, which is
not true.
Fixed by extending the search to  SYSROOT/*/*.

Signed-off-by: Jean-Mickael Guerin <jean-mickael.guerin@6wind.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

toolchain/helpers.mk

@@ -196,7 +196,7 @@ check_glibc_feature = \
 #
 check_glibc = \
 	SYSROOT_DIR="$(strip $1)"; \
-	if test `find $${SYSROOT_DIR}/lib/ -maxdepth 1 -name 'ld-linux*.so.*' -o -name 'ld.so.*' | wc -l` -eq 0 ; then \
+	if test `find $${SYSROOT_DIR}/ -maxdepth 2 -name 'ld-linux*.so.*' -o -name 'ld.so.*' | wc -l` -eq 0 ; then \
 		echo "Incorrect selection of the C library"; \
 		exit -1; \
 	fi; \