Add xcalloc wrapper

malloc and realloc are called through xmalloc and xrealloc, so calloc should
be called through xcalloc.
---
 st.c |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

st.c

@@ -324,6 +324,7 @@ static int isfullutf8(char *, int);
 
 static void *xmalloc(size_t);
 static void *xrealloc(void *, size_t);
+static void *xcalloc(size_t nmemb, size_t size);
 
 static void (*handler[LASTEvent])(XEvent *) = {
 	[KeyPress] = kpress,
@@ -373,6 +374,14 @@ xrealloc(void *p, size_t len) {
 	return p;
 }
 
+void *
+xcalloc(size_t nmemb, size_t size) {
+	void *p = calloc(nmemb, size);
+	if(!p)
+		die("Out of memory\n");
+	return p;
+}
+
 int
 utf8decode(char *s, long *u) {
 	uchar c;
@@ -1801,8 +1810,8 @@ tresize(int col, int row) {
 	/* allocate any new rows */
 	for(/* i == minrow */; i < row; i++) {
 		term.dirty[i] = 1;
-		term.line[i] = calloc(col, sizeof(Glyph));
-		term.alt [i] = calloc(col, sizeof(Glyph));
+		term.line[i] = xcalloc(col, sizeof(Glyph));
+		term.alt [i] = xcalloc(col, sizeof(Glyph));
 	}
 	if(col > term.col) {
 		bool *bp = term.tabs + term.col;