package/poco: Update check for uclibc toolchain

LIBC is really only used to construct the target tuple. To check if we
are using a uClibc toolchain, we use BR2_TOOLCHAIN_USES_UCLIBC.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/poco/poco.mk

@@ -28,7 +28,7 @@ POCO_OMIT = Data/ODBC PageCompiler \
 	$(if $(BR2_PACKAGE_POCO_DATA_MYSQL),,Data/MySQL) \
 	$(if $(BR2_PACKAGE_POCO_DATA_SQLITE),,Data/SQLite)
 
-ifeq ($(LIBC),uclibc)
+ifeq ($(BR2_TOOLCHAIN_USES_UCLIBC),y)
 POCO_CONF_OPTS += --no-fpenvironment --no-wstring
 endif