libbb: introduce and use xrealloc_vector

function                                             old     new   delta
xrealloc_vector_helper                                 -      51     +51
create_list                                           84      99     +15
getopt_main                                          690     695      +5
passwd_main                                         1049    1053      +4
get_cached                                            85      89      +4
msh_main                                            1377    1380      +3
add_match                                             42      41      -1
read_lines                                           720     718      -2
grave                                               1068    1066      -2
fill_match_lines                                     143     141      -2
add_to_dirlist                                        67      65      -2
add_input_file                                        49      47      -2
act                                                  252     250      -2
fsck_main                                           2252    2246      -6
man_main                                             765     757      -8
bb_internal_initgroups                               228     220      -8
cut_main                                            1052    1041     -11
add_edge_to_node                                      55      43     -12
dpkg_main                                           3851    3835     -16
ifupdown_main                                       2202    2178     -24
sort_main                                            838     812     -26
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 5/15 up/down: 82/-124)          Total: -42 bytes

1 files changed, 8 insertions, 4 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 378cb4401..fc65d52ff 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -564,10 +564,14 @@ void fputc_printable(int ch, FILE *file) FAST_FUNC;
 
 /* dmalloc will redefine these to it's own implementation. It is safe
  * to have the prototypes here unconditionally.  */
-extern void *malloc_or_warn(size_t size) FAST_FUNC;
-extern void *xmalloc(size_t size) FAST_FUNC;
-extern void *xzalloc(size_t size) FAST_FUNC;
-extern void *xrealloc(void *old, size_t size) FAST_FUNC;
+void *malloc_or_warn(size_t size) FAST_FUNC;
+void *xmalloc(size_t size) FAST_FUNC;
+void *xzalloc(size_t size) FAST_FUNC;
+void *xrealloc(void *old, size_t size) FAST_FUNC;
+#define xrealloc_vector(vector, shift, idx) \
+	xrealloc_vector_helper((vector), (sizeof((vector)[0]) << 8) + (shift), (idx))
+void* xrealloc_vector_helper(void *vector, unsigned sizeof_and_shift, int idx) FAST_FUNC;
+
 
 extern ssize_t safe_read(int fd, void *buf, size_t count) FAST_FUNC;
 extern ssize_t nonblock_safe_read(int fd, void *buf, size_t count) FAST_FUNC;