[common] Make hb_malloc() et al public

New API:
+hb_malloc()
+hb_calloc()
+hb_realloc()
+hb_free()

docs/harfbuzz-sections.txt

@@ -184,6 +184,10 @@ uint8_t
 HB_EXTERN
 HB_DEPRECATED
 HB_DEPRECATED_FOR
+hb_malloc
+hb_calloc
+hb_realloc
+hb_free
 <SUBSECTION Private>
 HB_H_IN
 HB_OT_H_IN

src/fontations/lib.rs

@@ -24,13 +24,6 @@ use skrifa::outline::DrawSettings;
 use skrifa::OutlineGlyphCollection;
 use skrifa::{GlyphId, MetadataProvider};
 
-extern "C" {
-    pub fn hb_malloc(_: usize) -> *const ::std::os::raw::c_void;
-    pub fn hb_calloc(_: usize, _: usize) -> *const ::std::os::raw::c_void;
-    pub fn hb_realloc(_: *const ::std::os::raw::c_void, _: usize) -> *const ::std::os::raw::c_void;
-    pub fn hb_free(_: *const ::std::os::raw::c_void);
-}
-
 struct MyAllocator;
 
 unsafe impl GlobalAlloc for MyAllocator {
@@ -43,7 +36,7 @@ unsafe impl GlobalAlloc for MyAllocator {
     }
 
     unsafe fn realloc(&self, ptr: *mut u8, _layout: Layout, new_size: usize) -> *mut u8 {
-        hb_realloc(ptr as *const c_void, new_size) as *mut u8
+        hb_realloc(ptr as *mut c_void, new_size) as *mut u8
     }
 
     unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {

src/hb-common.cc

@@ -1217,6 +1217,58 @@ uint8_t
   return hb_color_get_blue (color);
 }
 
+/**
+ * hb_malloc:
+ * @size: The size of the memory to allocate.
+ *
+ * Allocates @size bytes of memory, using the allocator set at
+ * compile-time. Typically just malloc().
+ *
+ * Return value: A pointer to the allocated memory.
+ *
+ * XSince: REPLACEME
+ **/
+void* hb_malloc(size_t size) { return hb_malloc_impl (size); }
+
+/**
+ * hb_calloc:
+ * @nmemb: The number of elements to allocate.
+ * @size: The size of each element.
+ *
+ * Allocates @nmemb elements of @size bytes each, initialized to zero,
+ * using the allocator set at compile-time. Typically just calloc().
+ *
+ * Return value: A pointer to the allocated memory.
+ *
+ * XSince: REPLACEME
+ **/
+void* hb_calloc(size_t nmemb, size_t size) { return hb_calloc_impl (nmemb, size); }
+
+/**
+ * hb_realloc:
+ * @ptr: The pointer to the memory to reallocate.
+ * @size: The new size of the memory.
+ *
+ * Reallocates the memory pointed to by @ptr to @size bytes, using the
+ * allocator set at compile-time. Typically just realloc().
+ *
+ * Return value: A pointer to the reallocated memory.
+ *
+ * XSince: REPLACEME
+ **/
+void* hb_realloc(void *ptr, size_t size) { return hb_realloc_impl (ptr, size); }
+
+/**
+ * hb_free:
+ * @ptr: The pointer to the memory to free.
+ *
+ * Frees the memory pointed to by @ptr, using the allocator set at
+ * compile-time. Typically just free().
+ *
+ * XSince: REPLACEME
+ **/
+void  hb_free(void *ptr) { hb_free_impl (ptr); }
+
 
 /* If there is no visibility control, then hb-static.cc will NOT
  * define anything.  Instead, we get it to define one set in here

src/hb-common.h

@@ -65,6 +65,7 @@ typedef unsigned __int64 uint64_t;
 #else
 #  include <inttypes.h>
 #endif
+#include <stddef.h>
 
 #if defined(__GNUC__) && ((__GNUC__ > 3) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
 #define HB_DEPRECATED __attribute__((__deprecated__))
@@ -948,6 +949,16 @@ typedef struct hb_glyph_extents_t {
  */
 typedef struct hb_font_t hb_font_t;
 
+/* Not of much use to clients. */
+HB_EXTERN void*
+hb_malloc (size_t size);
+HB_EXTERN void*
+hb_calloc (size_t nmemb, size_t size);
+HB_EXTERN void*
+hb_realloc (void *ptr, size_t size);
+HB_EXTERN void
+hb_free (void *ptr);
+
 HB_END_DECLS
 
 #endif /* HB_COMMON_H */

src/hb-static.cc

@@ -40,12 +40,8 @@
 #include "hb-ot-hmtx-table.hh"
 #include "hb-ot-maxp-table.hh"
 
-void* hb_malloc(size_t size) { return hb_malloc_impl (size); }
-void* hb_calloc(size_t nmemb, size_t size) { return hb_calloc_impl (nmemb, size); }
-void* hb_realloc(void *ptr, size_t size) { return hb_realloc_impl (ptr, size); }
-void  hb_free(void *ptr) { hb_free_impl (ptr); }
-
 #ifndef HB_NO_VISIBILITY
+
 #include "hb-ot-name-language-static.hh"
 
 uint64_t const _hb_NullPool[(HB_NULL_POOL_SIZE + sizeof (uint64_t) - 1) / sizeof (uint64_t)] = {};

src/hb.hh

@@ -533,10 +533,6 @@ extern "C" void  hb_free_impl(void *ptr);
 #define hb_realloc_impl realloc
 #define hb_free_impl free
 #endif
-extern "C" void* hb_malloc(size_t size);
-extern "C" void* hb_calloc(size_t nmemb, size_t size);
-extern "C" void* hb_realloc(void *ptr, size_t size);
-extern "C" void  hb_free(void *ptr);