Framework submodule: fix the libtestdriver1 build
`make -C tests libtestdriver1` copies `library/Makefile` to
`tests/libtestdriver1/library/Makefile`, where `../framework` does not point
to the framework submodule.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/Makefile b/library/Makefile
index d5e4f64..67f91f6 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -1,4 +1,8 @@
-include ../framework/exported.make
+ifndef MBEDTLS_PATH
+MBEDTLS_PATH := ..
+endif
+
+include $(MBEDTLS_PATH)/framework/exported.make
# Also see "include/mbedtls/mbedtls_config.h"