Add explicit cast to silence a warning

for #1710

interface/lapack/laswp.c

@@ -97,7 +97,7 @@ int NAME(blasint *N, FLOAT *a, blasint *LDA, blasint *K1, blasint *K2, blasint *
 
   blas_level1_thread(mode, n, k1, k2, dummyalpha,
 		     a, lda, NULL, 0, ipiv, incx,
-		     laswp[flag], nthreads);
+		     (int(*)())laswp[flag], nthreads);
   }
 #endif