Update from Gnulib

This incorporates:
2020-08-11 Use expression statements also on clang
2020-08-10 Use many __attribute__s with clang
2020-08-09 Use attribute __aligned__ with clang
2020-08-09 Use __alignof__ with clang
2020-08-09 ignore-value: Simplify on clang
2020-08-09 Use __typeof__ with clang
2020-08-09 intprops: Fix typo in comment
2020-08-09 Silence warnings from clang 10 with -Wimplicit-fallthrough
2020-08-09 count-one-bits: Use __builtin_popcount{,l,ll} on clang
2020-08-09 string: Fix build error in C++ mode with clang
2020-08-09 Add ability to emit user-defined diagnostics with clang
2020-08-07 alloca: No need to compile alloca.c with clang
2020-08-06 Use __builtin_assume with clang
* lib/alloca.in.h, lib/arg-nonnull.h, lib/c++defs.h, lib/cdefs.h:
* lib/count-one-bits.h, lib/dirent.in.h, lib/ignore-value.h:
* lib/intprops.h, lib/malloca.h, lib/regex_internal.h:
* lib/stdalign.in.h, lib/stddef.in.h, lib/stdio.in.h:
* lib/stdlib.in.h, lib/string.in.h, lib/verify.h, lib/warn-on-use.h:
* m4/gnulib-common.m4, m4/stddef_h.m4, m4/stdint.m4:
Copy from Gnulib.

1 files changed, 22 insertions, 9 deletions

diff --git a/lib/warn-on-use.h b/lib/warn-on-use.h
index 23c10fdd122..3f728d1a9dc 100644
--- a/lib/warn-on-use.h
+++ b/lib/warn-on-use.h
@@ -87,6 +87,13 @@
 extern __typeof__ (function) function __attribute__ ((__warning__ (message)))
 #  define _GL_WARN_ON_USE_ATTRIBUTE(message) \
   __attribute__ ((__warning__ (message)))
+# elif __clang_major__ >= 4
+/* Another compiler attribute is available in clang.  */
+#  define _GL_WARN_ON_USE(function, message) \
+extern __typeof__ (function) function \
+  __attribute__ ((__diagnose_if__ (1, message, "warning")))
+#  define _GL_WARN_ON_USE_ATTRIBUTE(message) \
+  __attribute__ ((__diagnose_if__ (1, message, "warning")))
 # elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
 /* Verify the existence of the function.  */
 #  define _GL_WARN_ON_USE(function, message) \
@@ -99,27 +106,33 @@ _GL_WARN_EXTERN_C int _gl_warn_on_use
 # endif
 #endif
 
-/* _GL_WARN_ON_USE_CXX (function, rettype, parameters_and_attributes, "string")
-   is like _GL_WARN_ON_USE (function, "string"), except that in C++ mode the
+/* _GL_WARN_ON_USE_CXX (function, rettype_gcc, rettype_clang, parameters_and_attributes, "message")
+   is like _GL_WARN_ON_USE (function, "message"), except that in C++ mode the
    function is declared with the given prototype, consisting of return type,
    parameters, and attributes.
    This variant is useful for overloaded functions in C++. _GL_WARN_ON_USE does
    not work in this case.  */
 #ifndef _GL_WARN_ON_USE_CXX
 # if !defined __cplusplus
-#  define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
+#  define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
      _GL_WARN_ON_USE (function, msg)
 # else
 #  if 4 < __GNUC__ || (__GNUC__ == 4 && 3 <= __GNUC_MINOR__)
-#   define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
-extern rettype function parameters_and_attributes \
-     __attribute__ ((__warning__ (msg)))
+/* A compiler attribute is available in gcc versions 4.3.0 and later.  */
+#   define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
+extern rettype_gcc function parameters_and_attributes \
+  __attribute__ ((__warning__ (msg)))
+#  elif __clang_major__ >= 4
+/* Another compiler attribute is available in clang.  */
+#   define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
+extern rettype_clang function parameters_and_attributes \
+  __attribute__ ((__diagnose_if__ (1, msg, "warning")))
 #  elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
 /* Verify the existence of the function.  */
-#   define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
-extern rettype function parameters_and_attributes
+#   define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
+extern rettype_gcc function parameters_and_attributes
 #  else /* Unsupported.  */
-#   define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
+#   define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
 _GL_WARN_EXTERN_C int _gl_warn_on_use
 #  endif
 # endif