[PATCH 11/17] maint: modernize IF_LINT for GCC 11.2.1

[Paul Eggert]

* src/cmp.c (cmp):
* src/dir.c (find_dir_file_pathname):
* src/sdiff.c (edit):
Mention which GCC bug this IF_LINT works around.
* src/diff3.c (process_diff):
Always initialize to NULL, to avoid problems on mostly-theoretical
hosts where accessing uninitialized variables traps.  The next
patch will have a better fix for this.
* src/ifdef.c (do_printf_spec):
No need for IF_LINT in GCC 11.2.1.
---
 src/cmp.c   | 2 +-
 src/diff3.c | 2 +-
 src/dir.c   | 5 +----
 src/ifdef.c | 2 +-
 src/sdiff.c | 4 ++--
 5 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/cmp.c b/src/cmp.c
index 9953d14..2e89ac1 100644
--- a/src/cmp.c
+++ b/src/cmp.c
@@ -390,7 +390,7 @@ cmp (void)
   char *buf1 = (char *) buffer1;
   int differing = 0;
   int f;
-  int offset_width IF_LINT (= 0);
+  int offset_width IF_LINT (= 0); /* IF_LINT due to GCC bug 101768.  */
 
   if (comparison_type == type_all_diffs)
     {
diff --git a/src/diff3.c b/src/diff3.c
index 09d987f..ccb7809 100644
--- a/src/diff3.c
+++ b/src/diff3.c
@@ -1009,7 +1009,7 @@ process_diff (char const *filea,
   lin i;
   struct diff_block *block_list;
   struct diff_block **block_list_end = &block_list;
-  struct diff_block *bptr IF_LINT (= NULL);
+  struct diff_block *bptr = NULL;
   size_t too_many_lines = (PTRDIFF_MAX
                            / MIN (sizeof *bptr->lines[1],
                                   sizeof *bptr->lengths[1]));
diff --git a/src/dir.c b/src/dir.c
index 01a32ab..3ffb953 100644
--- a/src/dir.c
+++ b/src/dir.c
@@ -339,10 +339,7 @@ dir_loop (struct comparison const *cmp, int i)
 char *
 find_dir_file_pathname (char const *dir, char const *file)
 {
-  /* The 'IF_LINT (volatile)' works around what appears to be a bug in
-     gcc 4.8.0 20120825; see
-     <http://lists.gnu.org/archive/html/bug-diffutils/2012-08/msg00007.html>.
-     */
+  /* IF_LINT due to GCC bug 21161.  */
   char const * IF_LINT (volatile) match = file;
 
   char *val;
diff --git a/src/ifdef.c b/src/ifdef.c
index 5a000cb..d82d2d1 100644
--- a/src/ifdef.c
+++ b/src/ifdef.c
@@ -329,7 +329,7 @@ do_printf_spec (FILE *out, char const *spec,
         return 0;
       else
         {
-          char value IF_LINT (= 0);
+          char value;
           f = scan_char_literal (f, &value);
           if (!f)
             return 0;
diff --git a/src/sdiff.c b/src/sdiff.c
index cc20dac..11e4da9 100644
--- a/src/sdiff.c
+++ b/src/sdiff.c
@@ -866,8 +866,8 @@ edit (struct line_filter *left, char const *lname, lin 
lline, lin llen,
 {
   for (;;)
     {
-      int cmd0 IF_LINT (= 0);
-      int cmd1 IF_LINT (= 0);
+      int cmd0;
+      int cmd1 IF_LINT (= 0);  /* IF_LINT due to GCC bug 101770.  */
       bool gotcmd = false;
 
       while (! gotcmd)
-- 
2.31.1