package/jsoncpp: switch build system to meson

Bumping jsoncpp to 1.9.1 will cause a CMake-related build error:
https://github.com/open-source-parsers/jsoncpp/issues/970

To fix the bug upstream suggests to switch to meson:
"Our official policy has been only supporting the meson build, and
 having users submit fixes for the CMake build."
https://github.com/open-source-parsers/jsoncpp/issues/970#issuecomment-509794015

Remove all _CONF_OPTS as they are not supported by meson.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/jsoncpp/jsoncpp.mk

@@ -10,15 +10,4 @@ JSONCPP_LICENSE = Public Domain or MIT
 JSONCPP_LICENSE_FILES = LICENSE
 JSONCPP_INSTALL_STAGING = YES
 
-JSONCPP_CONF_OPTS += \
-	-DJSONCPP_WITH_POST_BUILD_UNITTEST=OFF \
-	-DJSONCPP_WITH_TESTS=OFF \
-	-DJSONCPP_WITH_STRICT_ISO=OFF
-
-ifeq ($(BR2_SHARED_LIBS),y)
-JSONCPP_CONF_OPTS += -DBUILD_STATIC_LIBS=OFF
-else
-JSONCPP_CONF_OPTS += -DBUILD_STATIC_LIBS=ON
-endif
-
-$(eval $(cmake-package))
+$(eval $(meson-package))