buildsys: rm PT startfiles on realclean

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

Makerules

@@ -469,6 +469,8 @@ files.dep := $(libc-a-y) $(libc-so-y) $(libc-nonshared-y) \
 	$(libm-a-y) $(libm-so-y) \
 	$(libpthread-a-y) $(libpthread-so-y) $(libpthread-nonshared-y) \
 	$(libthread_db-a-y) $(libthread_db-so-y) $(libpthread-generated-y) \
+	$(START_FILE-libpthread.so) $(END_FILE-libpthread.so) \
+	$(PTHREAD_INITFINI:.c=.s) \
 	$(librt-a-y) $(librt-so-y)  $(libresolv-a-y) $(libresolv-so-y) \
 	$(libcrypt-a-y) $(libcrypt-so-y) $(libutil-a-y) $(libutil-so-y) \
 	$(libnsl-a-y) $(libnsl-so-y) $(ldso-y) $(libdl-a-y) $(libdl-so-y) \