libarchive: Avoid bogus conversion warning from PGI compiler

We cannot suppress PGI compiler warnings completely because even with
the "-w" flag the compiler still writes a message containing "compilation
completed with warnings" to stderr.

A warning is triggered by expressions like

  test ? NULL : ptr_to_const_char
  test ? ".." : ptr_to_const_char

that the PGI compiler handles incorrectly.  It chooses the pointer type
of the first option (either void* or char*) and warns about conversion
of the second without a cast.  Flip the expression logic to

  !test ? ptr_to_const_char : NULL
  !test ? ptr_to_const_char : ".."

to help the compiler choose the proper result type.

Utilities/cmlibarchive/libarchive/archive_options.c

@@ -41,9 +41,9 @@ _archive_set_option(struct archive *a,
 
 	archive_check_magic(a, magic, ARCHIVE_STATE_NEW, fn);
 
-	mp = m != NULL && m[0] == '\0' ? NULL : m;
-	op = o != NULL && o[0] == '\0' ? NULL : o;
-	vp = v != NULL && v[0] == '\0' ? NULL : v;
+	mp = m != NULL && m[0] != '\0' ? m : NULL;
+	op = o != NULL && o[0] != '\0' ? o : NULL;
+	vp = v != NULL && v[0] != '\0' ? v : NULL;
 
 	if (op == NULL && vp == NULL)
 		return (ARCHIVE_OK);

Utilities/cmlibarchive/libarchive/archive_read.c

@@ -902,7 +902,7 @@ static const char *
 _archive_filter_name(struct archive *_a, int n)
 {
 	struct archive_read_filter *f = get_filter(_a, n);
-	return f == NULL ? NULL : f->name;
+	return f != NULL ? f->name : NULL;
 }
 
 static int64_t

Utilities/cmlibarchive/libarchive/archive_read_support_format_7zip.c

@@ -1095,7 +1095,7 @@ init_decompression(struct archive_read *a, struct _7zip *zip,
 			}
 			archive_set_error(&a->archive, err,
 			    "Internal error initializing decompressor: %s",
-			    detail == NULL ? "??" : detail);
+			    detail != NULL ? detail : "??");
 			zip->bzstream_valid = 0;
 			return (ARCHIVE_FAILED);
 		}

Utilities/cmlibarchive/libarchive/archive_write.c

@@ -698,7 +698,7 @@ static const char *
 _archive_filter_name(struct archive *_a, int n)
 {
 	struct archive_write_filter *f = filter_lookup(_a, n);
-	return f == NULL ? NULL : f->name;
+	return f != NULL ? f->name : NULL;
 }
 
 static int64_t