uninorm, unistr: Improve GCC 11 allocation-deallocation checking

[Bruno Haible]

2021-08-07  Bruno Haible  <bruno@clisp.org>

        uninorm, unistr: Improve GCC 11 allocation-deallocation checking.
        * lib/uninorm.in.h (uninorm_filter_free): Move declaration up.
        (uninorm_filter_create): Declare that deallocation must happen through
        'uninorm_filter_free'.
        * lib/unistr.in.h: Include <stdlib.h>.
        (u8_strdup, u16_strdup, u32_strdup): Declare that deallocation must
        happen through 'free'.

diff --git a/lib/uninorm.in.h b/lib/uninorm.in.h
index 7c06911..d87ae27 100644
--- a/lib/uninorm.in.h
+++ b/lib/uninorm.in.h
@@ -209,6 +209,12 @@ extern int
    sequence to the encapsulated stream of Unicode characters.  */
 struct uninorm_filter;
 
+/* Bring data buffered in the filter to its destination, the encapsulated
+   stream, then close and free the filter.
+   Return 0 if successful, or -1 with errno set upon failure.  */
+extern int
+       uninorm_filter_free (struct uninorm_filter *filter);
+
 /* Create and return a normalization filter for Unicode characters.
    The pair (stream_func, stream_data) is the encapsulated stream.
    stream_func (stream_data, uc) receives the Unicode character uc
@@ -217,7 +223,8 @@ struct uninorm_filter;
 extern struct uninorm_filter *
        uninorm_filter_create (uninorm_t nf,
                               int (*stream_func) (void *stream_data, ucs4_t 
uc),
-                              void *stream_data);
+                              void *stream_data)
+       _GL_ATTRIBUTE_DEALLOC (uninorm_filter_free, 1);
 
 /* Stuff a Unicode character into a normalizing filter.
    Return 0 if successful, or -1 with errno set upon failure.  */
@@ -233,12 +240,6 @@ extern int
 extern int
        uninorm_filter_flush (struct uninorm_filter *filter);
 
-/* Bring data buffered in the filter to its destination, the encapsulated
-   stream, then close and free the filter.
-   Return 0 if successful, or -1 with errno set upon failure.  */
-extern int
-       uninorm_filter_free (struct uninorm_filter *filter);
-
 
 #ifdef __cplusplus
 }
diff --git a/lib/unistr.in.h b/lib/unistr.in.h
index ed65777..3b38207 100644
--- a/lib/unistr.in.h
+++ b/lib/unistr.in.h
@@ -25,6 +25,9 @@
 /* Get size_t, ptrdiff_t.  */
 #include <stddef.h>
 
+/* Get free().  */
+#include <stdlib.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -624,11 +627,14 @@ extern int
 /* Duplicate S, returning an identical malloc'd string.  */
 /* Similar to strdup(), wcsdup().  */
 extern uint8_t *
-       u8_strdup (const uint8_t *s);
+       u8_strdup (const uint8_t *s)
+       _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_DEALLOC_FREE;
 extern uint16_t *
-       u16_strdup (const uint16_t *s);
+       u16_strdup (const uint16_t *s)
+       _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_DEALLOC_FREE;
 extern uint32_t *
-       u32_strdup (const uint32_t *s);
+       u32_strdup (const uint32_t *s)
+       _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_DEALLOC_FREE;
 
 /* Find the first occurrence of UC in STR.  */
 /* Similar to strchr(), wcschr().  */