package/pcsc-lite: link with -latomic if needed

Link with -latomic if needed to avoid the following build failure since
bump to version 1.9.6 in commit b02f13cd54912f3dffd0e0863378050104430d77
and
https://github.com/LudovicRousseau/PCSC/commit/d56ed18dbebc4423506ce7f61d3e3bcf4bdc4cb0:

/nvmedata/autobuild/instance-11/output-1/host/lib/gcc/sparc-buildroot-linux-uclibc/10.3.0/../../../../sparc-buildroot-linux-uclibc/bin/ld: pcscd-readerfactory.o: undefined reference to symbol '__atomic_fetch_add_4@@LIBATOMIC_1.0'

Fixes:
 - http://autobuild.buildroot.org/results/80b2197a37073976a7dcec7b0f92dba1b26fb3f5

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

package/pcsc-lite/pcsc-lite.mk

@@ -45,4 +45,8 @@ ifeq ($(PACKAGE_PCSC_LITE_EMBEDDED),y)
 PCSC_LITE_CONF_OPTS += --enable-embedded
 endif
 
+ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
+PCSC_LITE_CONF_ENV += LIBS=-latomic
+endif
+
 $(eval $(autotools-package))