mbsrtoc32s, mbsnrtoc32s: Small optimization

[Bruno Haible]

Another small optimization of the same kind:


2023-07-11  Bruno Haible  <bruno@clisp.org>

        mbsrtoc32s, mbsnrtoc32s: Small optimization.
        * lib/mbsrtoc32s.c (USES_C32): Set to 0 when the module
        'mbrtoc32-regular' is in use.
        * lib/mbsnrtoc32s.c (USES_C32): Likewise.

diff --git a/lib/mbsnrtoc32s.c b/lib/mbsnrtoc32s.c
index 788eadd99e..0377a361d3 100644
--- a/lib/mbsnrtoc32s.c
+++ b/lib/mbsnrtoc32s.c
@@ -47,7 +47,13 @@ extern mbstate_t _gl_mbsrtoc32s_state;
 # define DCHAR_T char32_t
 # define INTERNAL_STATE _gl_mbsrtoc32s_state
 # define MBRTOWC mbrtoc32
-# define USES_C32 1
+# if GNULIB_MBRTOC32_REGULAR
+   /* If the 'mbrtoc32-regular' module is in use, we don't need to handle
+      a (size_t)(-3) return value from mbrtoc32.  */
+#  define USES_C32 0
+# else
+#  define USES_C32 1
+# endif
 # include "mbsnrtowcs-impl.h"
 
 #else
diff --git a/lib/mbsrtoc32s.c b/lib/mbsrtoc32s.c
index 92f7433818..19ec126b5f 100644
--- a/lib/mbsrtoc32s.c
+++ b/lib/mbsrtoc32s.c
@@ -39,7 +39,13 @@ extern mbstate_t _gl_mbsrtoc32s_state;
 # define DCHAR_T char32_t
 # define INTERNAL_STATE _gl_mbsrtoc32s_state
 # define MBRTOWC mbrtoc32
-# define USES_C32 1
+# if GNULIB_MBRTOC32_REGULAR
+   /* If the 'mbrtoc32-regular' module is in use, we don't need to handle
+      a (size_t)(-3) return value from mbrtoc32.  */
+#  define USES_C32 0
+# else
+#  define USES_C32 1
+# endif
 # include "mbsrtowcs-impl.h"
 
 #else