Replace memalign() with posix_memalign()

Memalign() is absent on some systems, use posix_memalign() instead.

src/common.c

@@ -1,10 +1,11 @@
+/* Make glibc happy with posix_memalign() */
+#define _POSIX_C_SOURCE 200112L
 
 #include "common.h"
 #include "array_defs.h"
 
 #include <stdio.h>
 #include <stdlib.h>
-#include <malloc.h>
 #include <string.h>
 
 void set_1d_array(real_t * arr, int length, real_t value, int stride);
@@ -155,8 +156,13 @@ void set_2d_array(real_t arr[LEN_2D][LEN_2D], real_t value, int stride)
 }
 
 void init(int** ip, real_t* s1, real_t* s2){
-    xx = (real_t*) memalign(ARRAY_ALIGNMENT, LEN_1D*sizeof(real_t));
-    *ip = (int *) memalign(ARRAY_ALIGNMENT, LEN_1D*sizeof(real_t));
+    int xx_errno = posix_memalign((void**)&xx, ARRAY_ALIGNMENT, LEN_1D*sizeof(real_t));
+    int ip_errno = posix_memalign((void**)ip, ARRAY_ALIGNMENT, LEN_1D*sizeof(real_t));
+
+    if (xx_errno || ip_errno) {
+        fprintf(stderr, "init: failed to allocate arrays\n");
+        exit(1);
+    }
 
     for (int i = 0; i < LEN_1D; i = i+5){
         (*ip)[i]   = (i+4);