package/kodi: explicitly link to libiconv when locales disabled

Fixes build error

/home/wbx/buildroot/output/host/lib/gcc/aarch64-buildroot-linux-uclibc/12.3.0/../../../../aarch64-buildroot-linux-uclibc/bin/ld:
build/utils/utils.a(CharsetConverter.cpp.o): undefined reference to symbol 'libiconv_open'
/home/wbx/buildroot/output/host/lib/gcc/aarch64-buildroot-linux-uclibc/12.3.0/../../../../aarch64-buildroot-linux-uclibc/bin/ld:
/home/wbx/buildroot/output/host/aarch64-buildroot-linux-uclibc/sysroot/usr/lib64/libiconv.so.2:
error adding symbols: DSO missing from command line

reported by Waldemar:
http://lists.busybox.net/pipermail/buildroot/2024-May/690952.html

Reproduced and fixed the build error using this defconfig:

BR2_x86_64=y
BR2_TOOLCHAIN_BUILDROOT_UCLIBC=y
BR2_TOOLCHAIN_BUILDROOT_WCHAR=y
BR2_TOOLCHAIN_BUILDROOT_CXX=y
BR2_PER_PACKAGE_DIRECTORIES=y
BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
BR2_PACKAGE_KODI=y
BR2_PACKAGE_MESA3D=y
BR2_PACKAGE_MESA3D_GALLIUM_DRIVER_IRIS=y
BR2_PACKAGE_MESA3D_OPENGL_EGL=y
BR2_PACKAGE_MESA3D_OPENGL_ES=y
BR2_PACKAGE_PYTHON3=y
BR2_PACKAGE_PYTHON3_PY_ONLY=y

Reported-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
[yann.morin.1998@free.fr: implement it similarly to KODI_C_FLAGS]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit f147e3b16a41324a9097ff17b002fd3c445e0f4c)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/kodi/kodi.mk

@@ -67,6 +67,7 @@ KODI_EXTRA_DOWNLOADS += \
 
 KODI_CONF_OPTS += \
 	-DCMAKE_C_FLAGS="$(TARGET_CFLAGS) $(KODI_C_FLAGS)" \
+	-DCMAKE_EXE_LINKER_FLAGS="$(KODI_EXTRA_LIBS)" \
 	-DENABLE_APP_AUTONAME=OFF \
 	-DENABLE_CCACHE=OFF \
 	-DENABLE_DVDCSS=ON \
@@ -127,6 +128,7 @@ KODI_CONF_OPTS += -DCORE_PLATFORM_NAME="$(KODI_CORE_PLATFORM_NAME)"
 
 ifeq ($(BR2_ENABLE_LOCALE),)
 KODI_DEPENDENCIES += libiconv
+KODI_EXTRA_LIBS += -liconv
 endif
 
 ifeq ($(BR2_arceb)$(BR2_arcle),y)