tree-wide: introduce mfree()

Pretty trivial helper which wraps free() but returns NULL, so we can
simplify this:
        free(foobar);
        foobar = NULL;
to this:
        foobar = mfree(foobar);

1 files changed, 2 insertions, 4 deletions

diff --git a/src/basic/copy.c b/src/basic/copy.c
index e2d356d676..33427c6a73 100644
--- a/src/basic/copy.c
+++ b/src/basic/copy.c
@@ -467,8 +467,7 @@ int copy_xattr(int fdf, int fdt) {
 
                 sza *= 2;
 
-                free(bufa);
-                bufa = NULL;
+                bufa = mfree(bufa);
         }
 
         p = bufa;
@@ -491,8 +490,7 @@ int copy_xattr(int fdf, int fdt) {
                         if (m < 0) {
                                 if (errno == ERANGE) {
                                         szb *= 2;
-                                        free(bufb);
-                                        bufb = NULL;
+                                        bufb = mfree(bufb);
                                         continue;
                                 }