Tidy up some compile warnings

eu018.c

@@ -19,14 +19,14 @@ void eu018(char *ans) {
 63 66 04 68 89 53 67 30 73 16 69 87 40 31 \
 04 62 98 27 23 09 70 98 73 93 38 53 60 04 23";
   int n = 0;
-  int *maxima = malloc(N*sizeof(int));
-  int *row = malloc(N*sizeof(int));
+  int *maxima = malloc(N * sizeof(int));
+  int *row = malloc(N * sizeof(int));
 
-  memset(maxima, 0, sizeof(maxima));
+  memset(maxima, 0, N * sizeof(int));
   for (int i = 0; i < N; i++) {
-    int *newmax = malloc(N*sizeof(int));
-    memset(newmax, 0, sizeof(newmax));
-    memset(row, 0, sizeof(row));
+    int *newmax = malloc(N * sizeof(int));
+    memset(newmax, 0, N * sizeof(int));
+    memset(row, 0, N * sizeof(int));
     for (int j = 0; j <= i; j++) {
       row[j] = atoi(data + 3 * n);
       n++;

eu066.c

@@ -1,7 +1,5 @@
 #include "euler.h"
 
-static char buf[10000];
-
 static int issquare(int n) {
   int sqrtn = sqrt(n);
   if (sqrtn * sqrtn == n)

eu069.c

@@ -10,8 +10,7 @@ void eu069(char *ans) {
   // is less than 1,000,000.
 
   static int primes[50];
-  int nprimes;
-  nprimes = genprimes(primes, 50);
+  genprimes(primes, 50);
 
   int product = 1;