bctoolbox: disable rpath

By default, bctoolbox adds the rpath to the shared library. Prevent this
by setting `CMAKE_SKIP_RPATH` [1] to a true value.

[1] https://cmake.org/cmake/help/latest/variable/CMAKE_SKIP_RPATH.html

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/bctoolbox/bctoolbox.mk

@@ -11,11 +11,14 @@ BCTOOLBOX_LICENSE_FILES = COPYING
 BCTOOLBOX_DEPENDENCIES = mbedtls
 BCTOOLBOX_INSTALL_STAGING = YES
 
+# Set CMAKE_SKIP_RPATH to prevent bctoolbox from adding the rpath to
+# shared library.
 BCTOOLBOX_CONF_OPTS = \
 	-DENABLE_STRICT=OFF \
 	-DENABLE_TESTS_COMPONENT=OFF \
 	-DENABLE_TESTS=OFF \
-	-DGIT_EXECUTABLE=OFF
+	-DGIT_EXECUTABLE=OFF \
+	-DCMAKE_SKIP_RPATH=ON
 
 # bctoolbox can be build with mbedTLS or PolarSSL support. If both
 # libraries are present, mbedTLS is preferred over PolarSSL.