add some f2c runtime functions, remove exception, avoid name conflict with libgfortran

lib/linalg/pow_lmp_dd.cpp

@@ -0,0 +1,12 @@
+
+#include "lmp_f2c.h"
+#undef abs
+
+#include <cmath>
+
+extern "C" {
+double pow_lmp_dd(doublereal *ap, doublereal *bp)
+{
+    return (pow(*ap, *bp));
+}
+}