package/clamav: fix CLAMAV_LIBS

The LIBS environment variable is ignored since bump to version 1.0.1 and
switch to cmake build system in commit
203725a46bc6b61ed7e4fdb3d76f62327d3e47fa resulting in the following
build failure:

/home/buildroot/autobuild/run/instance-3/output-1/host/opt/ext-toolchain/bin/../lib/gcc/arm-buildroot-linux-musleabihf/12.3.0/../../../../arm-buildroot-linux-musleabihf/bin/ld: CMakeFiles/clamonacc.dir/inotif/hash.c.o: in function `onas_ht_add_hierarchy':
hash.c:(.text+0xa84): undefined reference to `fts_open'

Fixes: 203725a46bc6b61ed7e4fdb3d76f62327d3e47fa
 - http://autobuild.buildroot.org/results/fe71ab29d02caeed609f1a181fccbd46b6feff65

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

package/clamav/clamav.mk

@@ -45,9 +45,8 @@ CLAMAV_DEPENDENCIES += musl-fts
 CLAMAV_LIBS += -lfts
 endif
 
-CLAMAV_CONF_ENV += LIBS="$(CLAMAV_LIBS)"
-
 CLAMAV_CONF_OPTS = \
+	-DCMAKE_EXE_LINKER_FLAGS="$(CLAMAV_LIBS)" \
 	-DCMAKE_SKIP_INSTALL_RPATH=ON \
 	-DENABLE_JSON_SHARED=ON \
 	-DENABLE_MAN_PAGES=OFF \