Tests: Revise FindBLAS test to avoid cblas_ mangling

Tests/FindBLAS/Test/main.c

@@ -2,13 +2,15 @@
 #include <string.h>
 
 // declare what parts of the blas C-API we need
-void cblas_dswap(const int N, double* X, const int incX, double* Y,
-                 const int incY);
+void dswap_(int* N, double* X, int* incX, double* Y, int* incY);
 
 int main()
 {
   double x[4] = { 1, 2, 3, 4 };
   double y[4] = { 8, 7, 7, 6 };
-  cblas_dswap(4, x, 1, y, 1);
+  int N = 4;
+  int incX = 1;
+  int incY = 1;
+  dswap_(&N, x, &incX, y, &incY);
   return 0;
 }