lib: move memchr()

Allow the function to be individually linkable, discardable, and
overridable.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <jgrall@amazon.com>

xen/common/string.c

@@ -311,28 +311,6 @@ char *(strstr)(const char *s1, const char *s2)
 }
 #endif
 
-#ifndef __HAVE_ARCH_MEMCHR
-/**
- * memchr - Find a character in an area of memory.
- * @s: The memory area
- * @c: The byte to search for
- * @n: The size of the area.
- *
- * returns the address of the first occurrence of @c, or %NULL
- * if @c is not found
- */
-void *(memchr)(const void *s, int c, size_t n)
-{
-	const unsigned char *p = s;
-
-	while (n--)
-		if ((unsigned char)c == *p++)
-			return (void *)(p - 1);
-
-	return NULL;
-}
-#endif
-
 /**
  * memchr_inv - Find an unmatching character in an area of memory.
  * @s: The memory area

xen/lib/Makefile

@@ -4,6 +4,7 @@ lib-y += bsearch.o
 lib-y += ctors.o
 lib-y += ctype.o
 lib-y += list-sort.o
+lib-y += memchr.o
 lib-y += memcmp.o
 lib-y += memcpy.o
 lib-y += memmove.o

xen/lib/memchr.c

@@ -0,0 +1,35 @@
+/*
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <xen/string.h>
+
+/**
+ * memchr - Find a character in an area of memory.
+ * @s: The memory area
+ * @c: The byte to search for
+ * @n: The size of the area.
+ *
+ * returns the address of the first occurrence of @c, or %NULL
+ * if @c is not found
+ */
+void *(memchr)(const void *s, int c, size_t n)
+{
+	const unsigned char *p = s;
+
+	while (n--)
+		if ((unsigned char)c == *p++)
+			return (void *)(p - 1);
+
+	return NULL;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * indent-tabs-mode: t
+ * End:
+ */