Avoid "format not a string literal and no format arguments"

In file included from vmod_file.c:44:
vmod_file.c: In function ‘check’:
/usr/include/varnish/cache/cache.h:66:26: error: format not a string literal and no format arguments [-Werror=format-security]
   66 | #define NO_VXID ((struct vxids){0})
      |                          ^~~~~
vmod_file.c:171:32: note: in expansion of macro ‘NO_VXID’
  171 |                 VSL(SLT_Error, NO_VXID, errbuf);
      |                                ^~~~~~~
      ...

src/vmod_file.c

@@ -173,7 +173,7 @@ check(union sigval val)
 		}
 		VERRMSG(rdr, errbuf, "%s.%s: cannot open %s: %s", rdr->vcl_name,
 			rdr->obj_name, info->path, VAS_errtxt(errno));
-		VSL(SLT_Error, NO_VXID, errbuf);
+		VSL(SLT_Error, NO_VXID, "%s", errbuf);
 		flags |= RDR_ERROR;
 		goto out;
 	}
@@ -184,7 +184,7 @@ check(union sigval val)
 		VERRMSG(rdr, errbuf, "%s.%s: cannot read info about %s: %s",
 			rdr->vcl_name, rdr->obj_name, info->path,
 			VAS_errtxt(errno));
-		VSL(SLT_Error, NO_VXID, errbuf);
+		VSL(SLT_Error, NO_VXID, "%s", errbuf);
 		flags |= RDR_ERROR;
 		goto out;
 	}
@@ -192,7 +192,7 @@ check(union sigval val)
 	if (!S_ISREG(st.st_mode)) {
 		VERRMSG(rdr, errbuf, "%s.%s: %s is not a regular file",
 			rdr->vcl_name, rdr->obj_name, info->path);
-		VSL(SLT_Error, NO_VXID, errbuf);
+		VSL(SLT_Error, NO_VXID, "%s", errbuf);
 		flags |= RDR_ERROR;
 		goto out;
 	}
@@ -225,7 +225,7 @@ check(union sigval val)
 		VERRMSG(rdr, errbuf, "%s.%s: could not map %s: %s",
 			rdr->vcl_name, rdr->obj_name, info->path,
 			VAS_errtxt(errno));
-		VSL(SLT_Error, NO_VXID, errbuf);
+		VSL(SLT_Error, NO_VXID, "%s", errbuf);
 		flags |= RDR_ERROR;
 		goto out;
 	}
@@ -235,7 +235,7 @@ check(union sigval val)
 	    != 0) {
 		VERRMSG(rdr, errbuf, "%s.%s: madvise(SEQUENTIAL): %s",
 			rdr->vcl_name, rdr->obj_name, VAS_errtxt(err));
-		VSL(SLT_Error, NO_VXID, errbuf);
+		VSL(SLT_Error, NO_VXID, "%s", errbuf);
 		flags |= RDR_ERROR;
 		goto out;
 	}
@@ -243,7 +243,7 @@ check(union sigval val)
 	    != 0) {
 		VERRMSG(rdr, errbuf, "%s.%s: madvise(WILLNEED): %s",
 			rdr->vcl_name, rdr->obj_name, VAS_errtxt(err));
-		VSL(SLT_Error, NO_VXID, errbuf);
+		VSL(SLT_Error, NO_VXID, "%s", errbuf);
 		flags |= RDR_ERROR;
 		goto out;
 	}
@@ -277,7 +277,7 @@ check(union sigval val)
 				VERRMSG(rdr, errbuf, "%s.%s: unmap failed: %s",
 					rdr->vcl_name, rdr->obj_name,
 					VAS_errtxt(errno));
-				VSL(SLT_Error, NO_VXID, errbuf);
+				VSL(SLT_Error, NO_VXID, "%s", errbuf);
 				flags |= RDR_ERROR;
 			}
 		}