Remove _lib_iswprint preprocessor sym

Every platform we currently support provides iswprint(). Furthermore, the
adhoc fallbacks are incorrect; albeit, in practice probably good enough.

config_ast.h.in

@@ -110,7 +110,6 @@
 #mesondefine _lib_getexecname
 #mesondefine _lib_getrusage
 #mesondefine _lib_gettimeofday
-#mesondefine _lib_iswprint
 #mesondefine _lib_lchmod
 #mesondefine _lib_lchmod_fchmodat_fallback
 #mesondefine _lib_loadbind

features/meson.build

@@ -93,11 +93,6 @@ feature_data.set10('_lib_getrusage',
         args: feature_test_args))
 feature_data.set10('_lib_sigqueue',
     cc.has_function('sigqueue', prefix: '#include <signal.h>', args: feature_test_args))
-# TODO: Enable iswprint() detection when we understand why doing so causes the
-# `wchar` unit test to fail. For now we force it to false to use the AST definition.
-# feature_data.set10('_lib_iswprint',
-#     cc.has_function('iswprint', prefix: '#include <wctype.h>', args: feature_test_args))
-feature_data.set10('_lib_iswprint', 0)
 
 if not cc.has_function('isnanl', prefix: '#include <math.h>', args: feature_test_args)
     feature_data.set('isnanl', 'isnan')

src/cmd/ksh93/edit/vi.c

@@ -51,9 +51,6 @@
 #define genlen(str) ed_genlen(str)
 #define digit(c) ((c & ~STRIP) == 0 && isdigit(c))
 #define is_print(c) ((c & ~STRIP) || isprint(c))
-#if !_lib_iswprint && !defined(iswprint)
-#define iswprint(c) ((c & ~0177) || isprint(c))
-#endif  // !_lib_iswprint && !defined(iswprint)
 static_fn int _vi_isalph(int);
 static_fn int _vi_isblank(int);
 #define vi_isblank(v) _vi_isblank(virtual[v])

src/cmd/ksh93/sh/string.c

@@ -28,10 +28,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <wchar.h>
-
-#if _lib_iswprint
 #include <wctype.h>
-#endif
 
 #include "ast.h"
 #include "ast_assert.h"
@@ -42,12 +39,6 @@
 #include "shtable.h"
 #include "stk.h"
 
-#if !_lib_iswprint
-// On some platforms iswprint() may be macro so make sure we don't get a redefinition warning.
-#undef iswprint
-#define iswprint(c) (((c) & ~0377) || isprint(c))
-#endif
-
 #define sep(c) ((c) == '-' || (c) == '_')
 
 //