tools/ccanlint: add global .valgrind_suppressions file.

Seems like my local Ubuntu install is giving bogus warnings.  Allow
local valgrind overrides.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

.gitignore

 TAGS
 .depends
+.valgrind_suppressions
 *.d
 *.o
 libccan.a

tools/ccanlint/tests/tests_pass.c

@@ -3,6 +3,7 @@
 #include <ccan/take/take.h>
 #include <ccan/str/str.h>
 #include <ccan/foreach/foreach.h>
+#include <ccan/tal/path/path.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -17,6 +18,7 @@
 #include "tests_pass.h"
 
 bool do_valgrind = false;
+const char *valgrind_suppress = "";
 
 static const char *can_run(struct manifest *m)
 {
@@ -27,9 +29,18 @@ static const char *can_run(struct manifest *m)
 
 	if (!is_excluded("tests_pass_valgrind")
 	    && run_command(m, &timeleft, &output,
-			   "valgrind -q true"))
+			   "valgrind -q true")) {
+		const char *sfile;
+
 		do_valgrind = true;
 
+		/* Check for suppressions file for all of CCAN. */
+		sfile = path_join(m, ccan_dir, ".valgrind_suppressions");
+		if (path_is_file(sfile))
+			valgrind_suppress = tal_fmt(m, "--suppressions=%s",
+						    sfile);
+	}
+
 	return NULL;
 }
 
@@ -67,9 +78,9 @@ static void run_test(void *ctx,
 			run_command_async(i, *timeleft,
 					  "valgrind -q"
 					  " --leak-check=full"
-					  " --log-fd=3 %s %s"
+					  " --log-fd=3 %s %s %s"
 					  " 3> %s",
-					  options,
+					  valgrind_suppress, options,
 					  i->compiled[COMPILE_NORMAL],
 					  i->valgrind_log);
 			return;

tools/ccanlint/tests/tests_pass.h

 /* Set in tests_pass. */
 extern bool do_valgrind;
+extern const char *valgrind_suppress;
 
 extern struct ccanlint tests_pass_valgrind;

tools/ccanlint/tests/tests_pass_valgrind.c

@@ -251,10 +251,10 @@ static void run_under_debugger_vg(struct manifest *m, struct score *score)
 		return;
 
 	first = list_top(&score->per_file_errors, struct file_error, list);
-	command = tal_fmt(m, "valgrind --leak-check=full --db-attach=yes%s %s",
+	command = tal_fmt(m, "valgrind --leak-check=full --db-attach=yes%s %s %s",
 			  concat(score, per_file_options(&tests_pass_valgrind,
 							 first->file)),
-			  first->file->compiled[COMPILE_NORMAL]);
+			  valgrind_suppress, first->file->compiled[COMPILE_NORMAL]);
 	if (system(command))
 		doesnt_matter();
 }