scripts: move hash function from scripts/kconfig/ to scripts/include/

This function was originally added by commit 8af27e1d ("fixdep: use
hash table instead of a single array").

Move it to scripts/include/ so that other host programs can use it.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/include/hash.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef HASH_H
+#define HASH_H
+
+static inline unsigned int hash_str(const char *s)
+{
+	/* fnv32 hash */
+	unsigned int hash = 2166136261U;
+
+	for (; *s; s++)
+		hash = (hash ^ *s) * 0x01000193;
+	return hash;
+}
+
+#endif /* HASH_H */

scripts/kconfig/lkc.h

@@ -51,7 +51,6 @@ static inline void xfwrite(const void *str, size_t len, size_t count, FILE *out)
 }
 
 /* util.c */
-unsigned int strhash(const char *s);
 const char *file_lookup(const char *name);
 
 /* lexer.l */

scripts/kconfig/symbol.c

@@ -9,6 +9,7 @@
 #include <string.h>
 #include <regex.h>
 
+#include <hash.h>
 #include <xalloc.h>
 #include "internal.h"
 #include "lkc.h"
@@ -893,7 +894,7 @@ struct symbol *sym_lookup(const char *name, int flags)
 			case 'n': return &symbol_no;
 			}
 		}
-		hash = strhash(name);
+		hash = hash_str(name);
 
 		hash_for_each_possible(sym_hashtable, symbol, node, hash) {
 			if (symbol->name &&
@@ -936,7 +937,7 @@ struct symbol *sym_find(const char *name)
 		case 'n': return &symbol_no;
 		}
 	}
-	hash = strhash(name);
+	hash = hash_str(name);
 
 	hash_for_each_possible(sym_hashtable, symbol, node, hash) {
 		if (symbol->name &&

scripts/kconfig/util.c

@@ -8,20 +8,11 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <hash.h>
 #include <hashtable.h>
 #include <xalloc.h>
 #include "lkc.h"
 
-unsigned int strhash(const char *s)
-{
-	/* fnv32 hash */
-	unsigned int hash = 2166136261U;
-
-	for (; *s; s++)
-		hash = (hash ^ *s) * 0x01000193;
-	return hash;
-}
-
 /* hash table of all parsed Kconfig files */
 static HASHTABLE_DEFINE(file_hashtable, 1U << 11);
 
@@ -35,7 +26,7 @@ const char *file_lookup(const char *name)
 {
 	struct file *file;
 	size_t len;
-	int hash = strhash(name);
+	int hash = hash_str(name);
 
 	hash_for_each_possible(file_hashtable, file, node, hash)
 		if (!strcmp(name, file->name))