Forced LDFLAGS=-lm: xclock's configure.ac uses AC_SEARCH_LIBS(sincos, [m], ...) to detect -lm. The old GCC 4.6.4 toolchain treats sin/cos/sincos as builtins, so the search never adds -lm and the link fails with undefined references to sin/cos. Forcing LDFLAGS="$(TARGET_LDFLAGS) -lm" in $(PKG)_CONFIGURE_ENV fixes it. This is a GCC-version-specific quirk, not uClibc-specific, so a configure-env workaround is used instead of a gate (no regression on any toolchain).