[gcc r16-9568] libstdc++: Use static_cast on OpenBSD ctype_base masks

[Pietro Monteiro]

https://gcc.gnu.org/g:5b3ff4e500a8b5850465e2a6713664d63ad40293

commit r16-9568-g5b3ff4e500a8b5850465e2a6713664d63ad40293
Author: Pietro Monteiro <pietro@sociotechnical.xyz>
Date:   Thu Aug 20 11:54:58 2026 -0400

    libstdc++: Use static_cast on OpenBSD ctype_base masks
    
    Commit r17-3313-g15419a00a29342 fixed the build on newer OpenBSD
    versions.  However, on platforms where char is signed, the mask
    constants may be implicitly converted to negative values, causing
    overflow/signedness change warnings.  Add static_cast<mask>(...) to
    make the conversion explicit and silence the warnings.
    
    libstdc++-v3/ChangeLog:
    
            * config/os/bsd/openbsd/ctype_base.h: Use static_cast when
            setting the masks.
    
    Signed-off-by: Pietro Monteiro <pietro@sociotechnical.xyz>
    (cherry picked from commit 18f299849d3dd151b62e2214dfebaa5ecdebe9b5)

Diff:
---
 libstdc++-v3/config/os/bsd/openbsd/ctype_base.h | 44 ++++++++++++-------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/libstdc++-v3/config/os/bsd/openbsd/ctype_base.h b/libstdc++-v3/config/os/bsd/openbsd/ctype_base.h
index e1d982f81cd1..f77a8cc5f5fa 100644
--- a/libstdc++-v3/config/os/bsd/openbsd/ctype_base.h
+++ b/libstdc++-v3/config/os/bsd/openbsd/ctype_base.h
@@ -44,30 +44,30 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
 #ifdef _CTYPE_S
     // OpenBSD 7.5 uses this style of define.
-    static const mask upper	= _CTYPE_U;
-    static const mask lower	= _CTYPE_L;
-    static const mask alpha	= _CTYPE_U | _CTYPE_L;
-    static const mask digit	= _CTYPE_N;
-    static const mask xdigit	= _CTYPE_N | _CTYPE_X;
-    static const mask space	= _CTYPE_S;
-    static const mask print	= _CTYPE_P | _CTYPE_U | _CTYPE_L | _CTYPE_N | _CTYPE_B;
-    static const mask graph	= _CTYPE_P | _CTYPE_U | _CTYPE_L | _CTYPE_N;
-    static const mask cntrl	= _CTYPE_C;
-    static const mask punct	= _CTYPE_P;
-    static const mask alnum	= _CTYPE_U | _CTYPE_L | _CTYPE_N;
+    static const mask upper	= static_cast<mask>(_CTYPE_U);
+    static const mask lower	= static_cast<mask>(_CTYPE_L);
+    static const mask alpha	= static_cast<mask>(_CTYPE_U | _CTYPE_L);
+    static const mask digit	= static_cast<mask>(_CTYPE_N);
+    static const mask xdigit	= static_cast<mask>(_CTYPE_N | _CTYPE_X);
+    static const mask space	= static_cast<mask>(_CTYPE_S);
+    static const mask print	= static_cast<mask>(_CTYPE_P | _CTYPE_U | _CTYPE_L | _CTYPE_N | _CTYPE_B);
+    static const mask graph	= static_cast<mask>(_CTYPE_P | _CTYPE_U | _CTYPE_L | _CTYPE_N);
+    static const mask cntrl	= static_cast<mask>(_CTYPE_C);
+    static const mask punct	= static_cast<mask>(_CTYPE_P);
+    static const mask alnum	= static_cast<mask>(_CTYPE_U | _CTYPE_L | _CTYPE_N);
 #else
     // Older versions use this style.
-    static const mask upper	= _U;
-    static const mask lower	= _L;
-    static const mask alpha	= _U | _L;
-    static const mask digit	= _N;
-    static const mask xdigit	= _N | _X;
-    static const mask space	= _S;
-    static const mask print	= _P | _U | _L | _N | _B;
-    static const mask graph	= _P | _U | _L | _N;
-    static const mask cntrl	= _C;
-    static const mask punct	= _P;
-    static const mask alnum	= _U | _L | _N;
+    static const mask upper	= static_cast<mask>(_U);
+    static const mask lower	= static_cast<mask>(_L);
+    static const mask alpha	= static_cast<mask>(_U | _L);
+    static const mask digit	= static_cast<mask>(_N);
+    static const mask xdigit	= static_cast<mask>(_N | _X);
+    static const mask space	= static_cast<mask>(_S);
+    static const mask print	= static_cast<mask>(_P | _U | _L | _N | _B);
+    static const mask graph	= static_cast<mask>(_P | _U | _L | _N);
+    static const mask cntrl	= static_cast<mask>(_C);
+    static const mask punct	= static_cast<mask>(_P);
+    static const mask alnum	= static_cast<mask>(_U | _L | _N);
 #endif
 #if __cplusplus >= 201103L
     static const mask blank	= space;