convert linalg library from Fortran to C++

lib/linalg/xerbla.cpp

@@ -0,0 +1,30 @@
+
+#include <exception>
+#include <string>
+
+class LinalgException : public std::exception {
+  std::string message;
+
+ public:
+  LinalgException() = delete;
+
+  explicit LinalgException(const std::string &msg) { message = msg; }
+  const char *what() const noexcept override { return message.c_str(); }
+};
+
+extern "C" {
+
+#include "lmp_f2c.h"
+
+integer xerbla_(const char *srname, integer *info)
+{
+  std::string mesg = " ** On entry to ";
+  for (int i = 0; i < 1024; ++i) {
+    if ((srname[i] == '\0') || (srname[i] == ' ')) break;
+    mesg.push_back(srname[i]);
+  }
+  mesg += " parameter number " + std::to_string(*info) + " had an illegal value\n";
+  throw LinalgException(mesg);
+  return 0;
+}
+}