Fix C23 build by renaming variable 'true'

Reported by gcc 13.2 with -std=gnu2x:

xprop.c: In function ‘Handle_Question_Mark’:
xprop.c:1291:10: error: expected identifier or ‘(’ before ‘true’
 1291 |     long true;
      |          ^~~~
xprop.c:1293:49: error: lvalue required as unary ‘&’ operand
 1293 |     dformat = Scan_Exp(dformat, thunks, format, &true);
      |                                                 ^

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/xprop.c b/xprop.c
index 4a31804..df45477 100644
--- a/xprop.c
+++ b/xprop.c
@@ -1288,15 +1288,15 @@ Scan_Exp (const char *string, thunk *thunks, const char *format, long *value)
 static const char *
 Handle_Question_Mark (const char *dformat, thunk *thunks, const char *format)
 {
-    long true;
+    long is_true;
 
-    dformat = Scan_Exp(dformat, thunks, format, &true);
+    dformat = Scan_Exp(dformat, thunks, format, &is_true);
 
     if (*dformat != '(')
 	Fatal_Error("Bad conditional: '(' expected: %s.", dformat);
     ++dformat;
 
-    if (!true)
+    if (!is_true)
 	dformat = Skip_Past_Right_Paren(dformat);
 
     return dformat;