src/libFLAC/lpc.c : Restore missing conditional.

Git commit 9c2290ade5 in-correctly removed a conditional around
an fprintf. Thanks to mark4o on #xiph (freenode) for reporting
this.
diff --git a/src/libFLAC/lpc.c b/src/libFLAC/lpc.c
index f7c643a..5c6e175 100644
--- a/src/libFLAC/lpc.c
+++ b/src/libFLAC/lpc.c
@@ -288,6 +288,7 @@
 		for(j = 0; j < order; j++) {
 			sum += qlp_coeff[j] * (*(--history));
 			sumo += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*history);
+			if(sumo > 2147483647ll || sumo < -2147483648ll)
 				fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients: OVERFLOW, i=%u, j=%u, c=%d, d=%d, sumo=%" PRId64 "\n",i,j,qlp_coeff[j],*history,sumo);
 		}
 		*(residual++) = *(data++) - (sum >> lp_quantization);