Merge branch 'ab/free-and-null'

A common pattern to free a piece of memory and assign NULL to the
pointer that used to point at it has been replaced with a new
FREE_AND_NULL() macro.

* ab/free-and-null:
*.[ch] refactoring: make use of the FREE_AND_NULL() macro
coccinelle: make use of the "expression" FREE_AND_NULL() rule
coccinelle: add a rule to make "expression" code use FREE_AND_NULL()
coccinelle: make use of the "type" FREE_AND_NULL() rule
coccinelle: add a rule to make "type" code use FREE_AND_NULL()
git-compat-util: add a FREE_AND_NULL() wrapper around free(ptr); ptr = NULL

diff --cc alias.c
Simple merge

diff --cc apply.c
Simple merge

diff --cc attr.c
Simple merge

diff --cc blame.c
Simple merge

diff --cc branch.c
Simple merge

diff --cc builtin/am.c
Simple merge

diff --cc builtin/clean.c
Simple merge

diff --cc builtin/config.c
Simple merge

diff --cc builtin/index-pack.c
Simple merge

diff --cc builtin/pack-objects.c
Simple merge

diff --cc builtin/unpack-objects.c
Simple merge

diff --cc builtin/worktree.c
Simple merge

diff --cc config.c
Simple merge

diff --cc credential.c
Simple merge

diff --cc diff-lib.c
Simple merge

diff --cc diff.c
Simple merge

diff --cc diffcore-rename.c
Simple merge

diff --cc dir.c
Simple merge

diff --cc fast-import.c
Simple merge

diff --cc gpg-interface.c
Simple merge

diff --cc grep.c
index 1fca83be86525957158fc20d09c91b3208a1974e,909f35a98417eed473c39605caa1c684256a9b94..98733db623ae2a0c4b3c11b71e3560429ec975ff
--- 1/grep.c
--- 2/grep.c
+++ b/grep.c
@@@ -1953,10 -1773,9 +1950,9 @@@ void grep_source_clear_data(struct grep
  {
        switch (gs->type) {
        case GREP_SOURCE_FILE:
 -      case GREP_SOURCE_SHA1:
 +      case GREP_SOURCE_OID:
        case GREP_SOURCE_SUBMODULE:
-               free(gs->buf);
-               gs->buf = NULL;
+               FREE_AND_NULL(gs->buf);
                gs->size = 0;
                break;
        case GREP_SOURCE_BUF:

diff --cc help.c
Simple merge

diff --cc http.c
Simple merge

diff --cc imap-send.c
Simple merge

diff --cc line-log.c
Simple merge

diff --cc ll-merge.c
Simple merge

diff --cc mailinfo.c
Simple merge

diff --cc pathspec.c
Simple merge

diff --cc read-cache.c
Simple merge

diff --cc refs/files-backend.c
Simple merge

diff --cc remote-testsvn.c
Simple merge

diff --cc rerere.c
Simple merge

diff --cc sequencer.c
Simple merge

diff --cc sha1_file.c
Simple merge

diff --cc split-index.c
Simple merge

diff --cc transport.c
Simple merge

diff --cc tree-diff.c
Simple merge

diff --cc tree.c
Simple merge