1 files changed, 279 insertions, 0 deletions

diff --git a/gl/m4/uchar_h.m4 b/gl/m4/uchar_h.m4
new file mode 100644
index 00000000..b2309385
--- /dev/null
+++ b/gl/m4/uchar_h.m4
@@ -0,0 +1,279 @@
+# uchar_h.m4
+# serial 32
+dnl Copyright (C) 2019-2025 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl This file is offered as-is, without any warranty.
+
+dnl From Bruno Haible.
+dnl Prepare the overridden <uchar.h>.
+
+AC_DEFUN_ONCE([gl_UCHAR_H],
+[
+  AC_REQUIRE([gl_UCHAR_H_DEFAULTS])
+
+  gl_CHECK_NEXT_HEADERS([uchar.h])
+  if test $ac_cv_header_uchar_h = yes; then
+    HAVE_UCHAR_H=1
+  else
+    HAVE_UCHAR_H=0
+  fi
+  AC_SUBST([HAVE_UCHAR_H])
+
+  dnl On macOS 15, in C mode, <uchar.h> does not exist. But in C++ mode,
+  dnl it exists, and we need to #include_next it, otherwise we get an error
+  dnl "<cuchar> tried including <uchar.h> but didn't find libc++'s <uchar.h>
+  dnl  header."
+  m4_ifdef([gl_ANSI_CXX], [AC_REQUIRE([gl_ANSI_CXX])])
+  CXX_HAVE_UCHAR_H=0
+  if test "$CXX" != no; then
+    AC_CACHE_CHECK([whether the C++ compiler has <uchar.h>],
+      [gl_cv_cxx_have_uchar_h],
+      [dnl We can't use AC_LANG_PUSH([C++]) and AC_LANG_POP([C++]) here, due to
+       dnl an autoconf bug <https://savannah.gnu.org/support/?110294>.
+       cat > conftest.cpp <<\EOF
+#include <uchar.h>
+EOF
+       gl_command="$CXX $CXXFLAGS $CPPFLAGS -c conftest.cpp"
+       if AC_TRY_EVAL([gl_command]); then
+         gl_cv_cxx_have_uchar_h=yes
+       else
+         gl_cv_cxx_have_uchar_h=no
+       fi
+       rm -fr conftest*
+      ])
+    if test $gl_cv_cxx_have_uchar_h = yes; then
+      CXX_HAVE_UCHAR_H=1
+    fi
+  fi
+  AC_SUBST([CXX_HAVE_UCHAR_H])
+
+  gl_TYPE_CHAR8_T
+  gl_TYPE_CHAR16_T
+  gl_TYPE_CHAR32_T
+
+  dnl In C++ mode, clang defines 'char16_t' and 'char32_t' as built-in types
+  dnl on some platforms (e.g. OpenBSD 6.7), and as types defined by many
+  dnl header files (<limits.h>, <stddef.h>, <stdint.h>, <stdio.h>, <stdlib.h>
+  dnl and others) on some platforms (e.g. Mac OS X 10.13).
+  dnl The same thing may also happen for 'char8_t'; so, be prepared for it.
+  m4_ifdef([gl_ANSI_CXX], [AC_REQUIRE([gl_ANSI_CXX])])
+  CXX_HAS_UCHAR_TYPES=0
+  if test $HAVE_UCHAR_H = 0; then
+    if test "$CXX" != no; then
+      AC_CACHE_CHECK([whether the C++ compiler predefines the <uchar.h> types],
+        [gl_cv_cxx_has_uchar_types],
+        [dnl We can't use AC_LANG_PUSH([C++]) and AC_LANG_POP([C++]) here, due to
+         dnl an autoconf bug <https://savannah.gnu.org/support/?110294>.
+         cat > conftest.cpp <<\EOF
+#include <stddef.h>
+char16_t a;
+char32_t b;
+EOF
+         gl_command="$CXX $CXXFLAGS $CPPFLAGS -c conftest.cpp"
+         if AC_TRY_EVAL([gl_command]); then
+           gl_cv_cxx_has_uchar_types=yes
+         else
+           gl_cv_cxx_has_uchar_types=no
+         fi
+         rm -fr conftest*
+        ])
+      if test $gl_cv_cxx_has_uchar_types = yes; then
+        CXX_HAS_UCHAR_TYPES=1
+      fi
+    fi
+  fi
+  AC_SUBST([CXX_HAS_UCHAR_TYPES])
+  CXX_HAS_CHAR8_TYPE=0
+  if test $HAVE_UCHAR_H = 0; then
+    if test "$CXX" != no; then
+      AC_CACHE_CHECK([whether the C++ compiler predefines the char8_t type],
+        [gl_cv_cxx_has_char8_type],
+        [dnl We can't use AC_LANG_PUSH([C++]) and AC_LANG_POP([C++]) here, due to
+         dnl an autoconf bug <https://savannah.gnu.org/support/?110294>.
+         cat > conftest.cpp <<\EOF
+#include <stddef.h>
+char8_t a;
+EOF
+         gl_command="$CXX $CXXFLAGS $CPPFLAGS -c conftest.cpp"
+         if AC_TRY_EVAL([gl_command]); then
+           gl_cv_cxx_has_char8_type=yes
+         else
+           gl_cv_cxx_has_char8_type=no
+         fi
+         rm -fr conftest*
+        ])
+      if test $gl_cv_cxx_has_char8_type = yes; then
+        CXX_HAS_CHAR8_TYPE=1
+      fi
+    fi
+  fi
+  AC_SUBST([CXX_HAS_CHAR8_TYPE])
+
+  dnl Test whether a 'char32_t' can hold more characters than a 'wchar_t'.
+  gl_STDINT_BITSIZEOF([wchar_t], [gl_STDINT_INCLUDES])
+  if test $BITSIZEOF_WCHAR_T -lt 32; then
+    SMALL_WCHAR_T=1
+  else
+    SMALL_WCHAR_T=0
+  fi
+  dnl SMALL_WCHAR_T is expected to be 1 on 32-bit AIX, Cygwin, native Windows.
+  AC_SUBST([SMALL_WCHAR_T])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use, and which is not
+  dnl guaranteed by C11.
+  gl_WARN_ON_USE_PREPARE([[
+      #ifdef __HAIKU__
+       #include <stdint.h>
+      #endif
+      #include <uchar.h>
+    ]], [c32rtomb mbrtoc16 mbrtoc32])
+])
+
+AC_DEFUN_ONCE([gl_TYPE_CHAR8_T],
+[
+  dnl Determine whether gnulib's <uchar.h> would, if present, override char8_t.
+  AC_CACHE_CHECK([whether char8_t is correctly defined],
+    [gl_cv_type_char8_t_works],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[
+          #ifdef __HAIKU__
+           #include <stdint.h>
+          #endif
+          #include <uchar.h>
+          int verify[(char8_t)(-1) >= 0 && sizeof (char8_t) == sizeof (unsigned char) ? 1 : -1];
+          ]])
+       ],
+       [gl_cv_type_char8_t_works=yes],
+       [gl_cv_type_char8_t_works=no])
+    ])
+  if test $gl_cv_type_char8_t_works = no; then
+    GNULIBHEADERS_OVERRIDE_CHAR8_T=1
+  else
+    GNULIBHEADERS_OVERRIDE_CHAR8_T=0
+  fi
+  AC_SUBST([GNULIBHEADERS_OVERRIDE_CHAR8_T])
+])
+
+dnl On Haiku 2020, char16_t and char32_t are incorrectly defined.
+dnl See <https://dev.haiku-os.org/ticket/15990>.
+AC_DEFUN_ONCE([gl_TYPE_CHAR16_T],
+[
+  dnl Determine whether gnulib's <uchar.h> would, if present, override char16_t.
+  AC_CACHE_CHECK([whether char16_t is correctly defined],
+    [gl_cv_type_char16_t_works],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[
+          #ifdef __HAIKU__
+           #include <stdint.h>
+          #endif
+          #include <uchar.h>
+          /* For simplicity, assume that uint16_least_t is equivalent to
+             'unsigned short'.  */
+          int verify[(char16_t)(-1) >= 0 && sizeof (char16_t) == sizeof (unsigned short) ? 1 : -1];
+          ]])
+       ],
+       [gl_cv_type_char16_t_works=yes],
+       [gl_cv_type_char16_t_works=no])
+    ])
+  if test $gl_cv_type_char16_t_works = no; then
+    GNULIBHEADERS_OVERRIDE_CHAR16_T=1
+  else
+    GNULIBHEADERS_OVERRIDE_CHAR16_T=0
+  fi
+  AC_SUBST([GNULIBHEADERS_OVERRIDE_CHAR16_T])
+])
+AC_DEFUN_ONCE([gl_TYPE_CHAR32_T],
+[
+  dnl Determine whether gnulib's <uchar.h> would, if present, override char32_t.
+  AC_CACHE_CHECK([whether char32_t is correctly defined],
+    [gl_cv_type_char32_t_works],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM([[
+          #ifdef __HAIKU__
+           #include <stdint.h>
+          #endif
+          #include <uchar.h>
+          /* For simplicity, assume that uint32_least_t is equivalent to
+             'unsigned int'.  */
+          int verify[(char32_t)(-1) >= 0 && sizeof (char32_t) == sizeof (unsigned int) ? 1 : -1];
+          ]])
+       ],
+       [gl_cv_type_char32_t_works=yes],
+       [gl_cv_type_char32_t_works=no])
+    ])
+  if test $gl_cv_type_char32_t_works = no; then
+    GNULIBHEADERS_OVERRIDE_CHAR32_T=1
+  else
+    GNULIBHEADERS_OVERRIDE_CHAR32_T=0
+  fi
+  AC_SUBST([GNULIBHEADERS_OVERRIDE_CHAR32_T])
+])
+
+# gl_UCHAR_MODULE_INDICATOR([modulename])
+# sets the shell variable that indicates the presence of the given module
+# to a C preprocessor expression that will evaluate to 1.
+# This macro invocation must not occur in macros that are AC_REQUIREd.
+AC_DEFUN([gl_UCHAR_MODULE_INDICATOR],
+[
+  dnl Ensure to expand the default settings once only.
+  gl_UCHAR_H_REQUIRE_DEFAULTS
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+# Initializes the default values for AC_SUBSTed shell variables.
+# This macro must not be AC_REQUIREd.  It must only be invoked, and only
+# outside of macros or in macros that are not AC_REQUIREd.
+AC_DEFUN([gl_UCHAR_H_REQUIRE_DEFAULTS],
+[
+  m4_defun(GL_MODULE_INDICATOR_PREFIX[_UCHAR_H_MODULE_INDICATOR_DEFAULTS], [
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_BTOC32])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISALNUM])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISALPHA])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISBLANK])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISCNTRL])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISDIGIT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISGRAPH])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISLOWER])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISPRINT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISPUNCT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISSPACE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISUPPER])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32ISXDIGIT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32TOLOWER])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32TOUPPER])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32WIDTH])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32RTOMB])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32SNRTOMBS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32SRTOMBS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32STOMBS])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32SWIDTH])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32TOB])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32_APPLY_MAPPING])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32_APPLY_TYPE_TEST])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32_GET_MAPPING])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_C32_GET_TYPE_TEST])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBRTOC16])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBRTOC32])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSNRTOC32S])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSRTOC32S])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MBSTOC32S])
+  ])
+  m4_require(GL_MODULE_INDICATOR_PREFIX[_UCHAR_H_MODULE_INDICATOR_DEFAULTS])
+  AC_REQUIRE([gl_UCHAR_H_DEFAULTS])
+])
+
+AC_DEFUN([gl_UCHAR_H_DEFAULTS],
+[
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_C32RTOMB=1;             AC_SUBST([HAVE_C32RTOMB])
+  HAVE_MBRTOC16=1;             AC_SUBST([HAVE_MBRTOC16])
+  HAVE_MBRTOC32=1;             AC_SUBST([HAVE_MBRTOC32])
+  REPLACE_C32RTOMB=0;          AC_SUBST([REPLACE_C32RTOMB])
+  REPLACE_MBRTOC16=0;          AC_SUBST([REPLACE_MBRTOC16])
+  REPLACE_MBRTOC32=0;          AC_SUBST([REPLACE_MBRTOC32])
+])