patch 8.1.1414: alloc() returning "char_u *" causes a lot of type casts

Problem:    Alloc() returning "char_u *" causes a lot of type casts.
Solution:   Have it return "void *". (Mike Williams)  Define ALLOC_ONE() to
            check the simple allocations.
diff --git a/src/proto/misc2.pro b/src/proto/misc2.pro
index 687cfed..84ed66a 100644
--- a/src/proto/misc2.pro
+++ b/src/proto/misc2.pro
@@ -21,13 +21,13 @@
 int leftcol_changed(void);
 void vim_mem_profile_dump(void);
 int alloc_does_fail(size_t size);
-char_u *alloc(size_t size);
-char_u *alloc_id(size_t size, alloc_id_T id);
-char_u *alloc_clear(size_t size);
-char_u *alloc_clear_id(size_t size, alloc_id_T id);
-char_u *lalloc_clear(size_t size, int message);
-char_u *lalloc(size_t size, int message);
-char_u *lalloc_id(size_t size, int message, alloc_id_T id);
+void *alloc(size_t size);
+void *alloc_id(size_t size, alloc_id_T id);
+void *alloc_clear(size_t size);
+void *alloc_clear_id(size_t size, alloc_id_T id);
+void *lalloc_clear(size_t size, int message);
+void *lalloc(size_t size, int message);
+void *lalloc_id(size_t size, int message, alloc_id_T id);
 void *mem_realloc(void *ptr, size_t size);
 void do_outofmem_msg(size_t size);
 void free_all_mem(void);