diff -rupN gtk2hs-buildtools-0.13.5.0/c2hs/c/CLexer.x new-gtk2hs-buildtools-0.13.5.0/c2hs/c/CLexer.x
--- gtk2hs-buildtools-0.13.5.0/c2hs/c/CLexer.x	1970-01-01 01:00:00.000000000 +0100
+++ new-gtk2hs-buildtools-0.13.5.0/c2hs/c/CLexer.x	2025-08-01 14:51:49.676123965 +0200
@@ -130,7 +130,7 @@ $white+					;
 --  * allows further ints after the file name a la GCC; as the GCC CPP docu
 --   doesn't say how many ints there can be, we allow an unbound number
 --
-\#$space*@int$space*(\"($infname|@charesc)*\"$space*)?(@int$space*)*$eol
+\#$space*@digits$space*(\"($infname|@charesc)*\"$space*)?(@int$space*)*$eol
   { \pos len str -> setPos (adjustPos (take len str) pos) >> lexToken }
 
 -- #pragma directive (K&R A12.8)