[master] d23db4026 Use the right version of the vct_ishdrval() macro

[Nils Goroll]

commit d23db4026600c964915b873ed41520e993fc8327
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Fri Oct 9 14:36:42 2020 +0200

    Use the right version of the vct_ishdrval() macro
    
    I accidentally committed an earlier, wrong version. o/ Dridi
    
    Ref #3407
    
    https://github.com/varnishcache/varnish-cache/pull/3407#issuecomment-696146625

diff --git a/include/vct.h b/include/vct.h
index 92e4123b9..7ccbbf233 100644
--- a/include/vct.h
+++ b/include/vct.h
@@ -84,7 +84,8 @@ vct_is(int x, uint16_t y)
 #define vct_isxmlnamestart(x) vct_is(x, VCT_XMLNAMESTART)
 #define vct_isxmlname(x) vct_is(x, VCT_XMLNAMESTART | VCT_XMLNAME)
 #define vct_istchar(x) vct_is(x, VCT_ALPHA | VCT_DIGIT | VCT_TCHAR)
-#define vct_ishdrval(x) (((x) >= 0x20 && (x) != 0x7f) || (x) == 0x09)
+#define vct_ishdrval(x) \
+    (((uint8_t)(x) >= 0x20 && (uint8_t)(x) != 0x7f) ||(uint8_t)(x) == 0x09)
 
 static inline int
 vct_iscrlf(const char* p, const char* end)