motion: fix sdl-config detection

Overwrite ac_cv_path_CONFIG_SDL in case sdl development is installed on the host.

Fixes [1]:

ERROR: unsafe header/library path used in cross-compilation: '-I/usr/include/SDL'

[1] http://autobuild.buildroot.net/results/459/4592eb83efa393f77f5ee014f93a271f2313bee6

---
 package/motion/motion.mk | 3 +++
 1 file changed, 3 insertions(+)

index de29a2a..cf9be76 100644
@@ -54,6 +54,9 @@ endif
 ifeq ($(BR2_PACKAGE_SDL),y)
 MOTION_DEPENDENCIES += sdl
 MOTION_CONF_OPTS += --with-sdl=$(STAGING_DIR)/usr
+# overwrite ac_cv_path_CONFIG_SDL in case sdl development is
+# installed on the host
+MOTION_CONF_ENV += ac_cv_path_CONFIG_SDL=$(STAGING_DIR)/usr/bin/sdl-config
 else
 MOTION_CONF_OPTS += --without-sdl
 endif

2.8.1

Hello,

I've applied to master, however, one question below.

With the ac_cv_path_CONFIG_SDL, is this --with-sdl still really necessary?

If it uses the sdl-config script to get the SDL path, then it should theoretically no longer be needed.

Thanks,

Thomas

Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Hello Thomas,

If I read the code from configure.ac right '--with-sdl' is needed, but the given path could be omitted (as it is ignored in case a local/host version of sdl-config is found first, therefore ac_cv_path_CONFIG_SDL is needed):

211 #
212 # Check for sdl library
213 #
214 SDL_SUPPORT="no"
215 AC_ARG_WITH(sdl,
216 [ --with-sdl[=DIR] Specify the prefix for the install path for
217 sdl-config to get stream in SDL window (optional).
218 ],
219 [],
220 [withval="no"])
221 if test "x$withval" = "xno"; then
222 AC_MSG_CHECKING(for sdl)
223 AC_MSG_RESULT(skipped)

...sdl skipped without '--with-sdl' option...

224 else
225 AC_PATH_PROG([CONFIG_SDL], [sdl-config], [], [${PATH}:${withval}:${withval}/bin])

...sdl-config from local path taken before the one from given path...

226 if test -z "($CONFIG_SDL --version) 2>/dev/null" ;then

 227                 echo ""
 228                 echo "****************************************************"
 229                 echo "* sdl-config could not be found. Please install it *"
 230                 echo "* and remove the --with-sdl configure argument.    *"
 231                 echo "* libSDL can be found at http://www.libsdl.org     *"
 232                 echo "****************************************************"
 233                 echo ""
 234         else
 235                 SDL_SUPPORT="yes"
 236                 TEMP_LIBS="$TEMP_LIBS `${CONFIG_SDL} --libs`"
 237                 TEMP_CFLAGS="${TEMP_CFLAGS} `${CONFIG_SDL} --cflags`"
 238                 AC_DEFINE([HAVE_SDL],1,[Define to 1 if you have SDL support])
 239                 SDL_OBJ="sdl.o"
 240                 AC_SUBST(SDL_OBJ)

241 fi
242 fi

Regards,
Peter