update openmp pragmas for MSVC compatibility

This has no negative impact on Linux and is in preparation for windows support. Windows compiles will not work without additional timer and mmap compatibility patches

run.c

@@ -13,9 +13,11 @@ $ ./run
 #include <time.h>
 #include <math.h>
 #include <string.h>
-#include <unistd.h>
 #include <fcntl.h>
+#ifndef _WIN32
+#include <unistd.h>
 #include <sys/mman.h>
+#endif 
 
 // ----------------------------------------------------------------------------
 // Transformer and RunState structs, and related memory management
@@ -190,9 +192,9 @@ void softmax(float* x, int size) {
 
 void matmul(float* xout, float* x, float* w, int n, int d) {
     // W (d,n) @ x (n,) -> xout (d,)
-    #pragma omp parallel for
-    for (int i = 0; i < d; i++) {
-        float val = 0.0f;
+    int i;
+    #pragma omp parallel for private(i)
+    for (i = 0; i < d; i++) {        float val = 0.0f;
         for (int j = 0; j < n; j++) {
             val += w[i * n + j] * x[j];
         }
@@ -255,8 +257,9 @@ void transformer(int token, int pos, Config* p, RunState* s, TransformerWeights*
         memcpy(value_cache_row, s->v, dim*sizeof(*value_cache_row));
         
         // multihead attention. iterate over all heads
-        #pragma omp parallel for
-        for (int h = 0; h < p->n_heads; h++) {
+        int h;
+        #pragma omp parallel for private(h)
+        for (h = 0; h < p->n_heads; h++) {
             // get the query vector for this head
             float* q = s->q + h * head_size;
             // attention scores for this head