patch 8.0.1736: check for C99 features is incomplete

Problem:    Check for C99 features is incomplete.
Solution:   Use AC_PROG_CC_C99 and when C99 isn't fully supported check the
            features we need. (James McCoy, closes #2820)

src/auto/configure

@@ -3454,81 +3454,167 @@ ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
-   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $CC option to accept ISO C89" >&5
+   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $CC option to accept ISO C99" >&5
-$as_echo_n "checking for $CC option to accept ISO C89... " >&6; }
+$as_echo_n "checking for $CC option to accept ISO C99... " >&6; }
-if ${ac_cv_prog_cc_c89+:} false; then :
+if ${ac_cv_prog_cc_c99+:} false; then :
   $as_echo_n "(cached) " >&6
 else
-  ac_cv_prog_cc_c89=no
+  ac_cv_prog_cc_c99=no
 ac_save_CC=$CC
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <stdarg.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <wchar.h>
 #include <stdio.h>
-struct stat;
+
-/* Most of the following tests are stolen from RCS 5.7's src/conf.sh.  */
+// Check varargs macros.  These examples are taken from C99 6.10.3.5.
-struct buf { int x; };
+#define debug(...) fprintf (stderr, __VA_ARGS__)
-FILE * (*rcsopen) (struct buf *, struct stat *, int);
+#define showlist(...) puts (#__VA_ARGS__)
-static char *e (p, i)
+#define report(test,...) ((test) ? puts (#test) : printf (__VA_ARGS__))
-     char **p;
+static void
-     int i;
+test_varargs_macros (void)
 {
-  return p[i];
+  int x = 1234;
-}
+  int y = 5678;
-static char *f (char * (*g) (char **, int), char **p, ...)
+  debug ("Flag");
-{
+  debug ("X = %d\n", x);
-  char *s;
+  showlist (The first, second, and third items.);
-  va_list v;
+  report (x>y, "x is %d but y is %d", x, y);
-  va_start (v,p);
-  s = g (p, va_arg (v,int));
-  va_end (v);
-  return s;
 }
 
-/* OSF 4.0 Compaq cc is some sort of almost-ANSI by default.  It has
+// Check long long types.
-   function prototypes and stuff, but not '\xHH' hex character constants.
+#define BIG64 18446744073709551615ull
-   These don't provoke an error unfortunately, instead are silently treated
+#define BIG32 4294967295ul
-   as 'x'.  The following induces an error, until -std is added to get
+#define BIG_OK (BIG64 / BIG32 == 4294967297ull && BIG64 % BIG32 == 0)
-   proper ANSI mode.  Curiously '\x00'!='x' always comes out true, for an
+#if !BIG_OK
-   array size at least.  It's necessary to write '\x00'==0 to get something
+  your preprocessor is broken;
-   that's true only with -std.  */
+#endif
-int osf4_cc_array ['\x00' == 0 ? 1 : -1];
+#if BIG_OK
+#else
+  your preprocessor is broken;
+#endif
+static long long int bignum = -9223372036854775807LL;
+static unsigned long long int ubignum = BIG64;
 
-/* IBM C 6 for AIX is almost-ANSI by default, but it replaces macro parameters
+struct incomplete_array
-   inside strings and character constants.  */
+{
-#define FOO(x) 'x'
+  int datasize;
-int xlc6_cc_array[FOO(a) == 'x' ? 1 : -1];
+  double data[];
+};
+
+struct named_init {
+  int number;
+  const wchar_t *name;
+  double average;
+};
+
+typedef const char *ccp;
+
+static inline int
+test_restrict (ccp restrict text)
+{
+  // See if C++-style comments work.
+  // Iterate through items via the restricted pointer.
+  // Also check for declarations in for loops.
+  for (unsigned int i = 0; *(text+i) != '\0'; ++i)
+    continue;
+  return 0;
+}
+
+// Check varargs and va_copy.
+static void
+test_varargs (const char *format, ...)
+{
+  va_list args;
+  va_start (args, format);
+  va_list args_copy;
+  va_copy (args_copy, args);
+
+  const char *str;
+  int number;
+  float fnumber;
+
+  while (*format)
+    {
+      switch (*format++)
+	{
+	case 's': // string
+	  str = va_arg (args_copy, const char *);
+	  break;
+	case 'd': // int
+	  number = va_arg (args_copy, int);
+	  break;
+	case 'f': // float
+	  fnumber = va_arg (args_copy, double);
+	  break;
+	default:
+	  break;
+	}
+    }
+  va_end (args_copy);
+  va_end (args);
+}
 
-int test (int i, double x);
-struct s1 {int (*f) (int a);};
-struct s2 {int (*f) (double a);};
-int pairnames (int, char **, FILE *(*)(struct buf *, struct stat *, int), int, int);
-int argc;
-char **argv;
 int
 main ()
 {
-return f (e, argv, 0) != argv[0]  ||  f (e, argv, 1) != argv[1];
+
+  // Check bool.
+  _Bool success = false;
+
+  // Check restrict.
+  if (test_restrict ("String literal") == 0)
+    success = true;
+  char *restrict newvar = "Another string";
+
+  // Check varargs.
+  test_varargs ("s, d' f .", "string", 65, 34.234);
+  test_varargs_macros ();
+
+  // Check flexible array members.
+  struct incomplete_array *ia =
+    malloc (sizeof (struct incomplete_array) + (sizeof (double) * 10));
+  ia->datasize = 10;
+  for (int i = 0; i < ia->datasize; ++i)
+    ia->data[i] = i * 1.234;
+
+  // Check named initializers.
+  struct named_init ni = {
+    .number = 34,
+    .name = L"Test wide string",
+    .average = 543.34343,
+  };
+
+  ni.number = 58;
+
+  int dynamic_array[ni.number];
+  dynamic_array[ni.number - 1] = 543;
+
+  // work around unused variable warnings
+  return (!success || bignum == 0LL || ubignum == 0uLL || newvar[0] == 'x'
+	  || dynamic_array[ni.number - 1] != 543);
+
   ;
   return 0;
 }
 _ACEOF
-for ac_arg in '' -qlanglvl=extc89 -qlanglvl=ansi -std \
+for ac_arg in '' -std=gnu99 -std=c99 -c99 -AC99 -D_STDC_C99= -qlanglvl=extc99
-	-Ae "-Aa -D_HPUX_SOURCE" "-Xc -D__EXTENSIONS__"
 do
   CC="$ac_save_CC $ac_arg"
   if ac_fn_c_try_compile "$LINENO"; then :
-  ac_cv_prog_cc_c89=$ac_arg
+  ac_cv_prog_cc_c99=$ac_arg
 fi
 rm -f core conftest.err conftest.$ac_objext
-  test "x$ac_cv_prog_cc_c89" != "xno" && break
+  test "x$ac_cv_prog_cc_c99" != "xno" && break
 done
 rm -f conftest.$ac_ext
 CC=$ac_save_CC
 
 fi
 # AC_CACHE_VAL
-case "x$ac_cv_prog_cc_c89" in
+case "x$ac_cv_prog_cc_c99" in
   x)
     { $as_echo "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
 $as_echo "none needed" >&6; } ;;
@@ -3536,11 +3622,11 @@ $as_echo "none needed" >&6; } ;;
     { $as_echo "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
 $as_echo "unsupported" >&6; } ;;
   *)
-    CC="$CC $ac_cv_prog_cc_c89"
+    CC="$CC $ac_cv_prog_cc_c99"
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c89" >&5
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c99" >&5
-$as_echo "$ac_cv_prog_cc_c89" >&6; } ;;
+$as_echo "$ac_cv_prog_cc_c99" >&6; } ;;
 esac
-if test "x$ac_cv_prog_cc_c89" != xno; then :
+if test "x$ac_cv_prog_cc_c99" != xno; then :
 
 fi
 
@@ -4179,35 +4265,193 @@ $as_echo "#define HAVE_SYS_WAIT_H 1" >>confdefs.h
 fi
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler can handle Vim code" >&5
+if test x"$ac_cv_prog_cc_c99" != xno; then
-$as_echo_n "checking if the compiler can handle Vim code... " >&6; }
+
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for unsigned long long int" >&5
+$as_echo_n "checking for unsigned long long int... " >&6; }
+if ${ac_cv_type_unsigned_long_long_int+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_cv_type_unsigned_long_long_int=yes
+     if test "x${ac_cv_prog_cc_c99-no}" = xno; then
+       cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <stdio.h>
+
+  /* For now, do not test the preprocessor; as of 2007 there are too many
+	 implementations with broken preprocessors.  Perhaps this can
+	 be revisited in 2012.  In the meantime, code should not expect
+	 #if to work with literals wider than 32 bits.  */
+      /* Test literals.  */
+      long long int ll = 9223372036854775807ll;
+      long long int nll = -9223372036854775807LL;
+      unsigned long long int ull = 18446744073709551615ULL;
+      /* Test constant expressions.   */
+      typedef int a[((-9223372036854775807LL < 0 && 0 < 9223372036854775807ll)
+		     ? 1 : -1)];
+      typedef int b[(18446744073709551615ULL <= (unsigned long long int) -1
+		     ? 1 : -1)];
+      int i = 63;
+int
+main ()
+{
+/* Test availability of runtime routines for shift and division.  */
+      long long int llmax = 9223372036854775807ll;
+      unsigned long long int ullmax = 18446744073709551615ull;
+      return ((ll << 63) | (ll >> 63) | (ll < i) | (ll > i)
+	      | (llmax / ll) | (llmax % ll)
+	      | (ull << 63) | (ull >> 63) | (ull << i) | (ull >> i)
+	      | (ullmax / ull) | (ullmax % ull));
+  ;
+  return 0;
+}
+
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+
+else
+  ac_cv_type_unsigned_long_long_int=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+     fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_type_unsigned_long_long_int" >&5
+$as_echo "$ac_cv_type_unsigned_long_long_int" >&6; }
+  if test $ac_cv_type_unsigned_long_long_int = yes; then
+
+$as_echo "#define HAVE_UNSIGNED_LONG_LONG_INT 1" >>confdefs.h
+
+  fi
+
+
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for long long int" >&5
+$as_echo_n "checking for long long int... " >&6; }
+if ${ac_cv_type_long_long_int+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_cv_type_long_long_int=yes
+      if test "x${ac_cv_prog_cc_c99-no}" = xno; then
+	ac_cv_type_long_long_int=$ac_cv_type_unsigned_long_long_int
+	if test $ac_cv_type_long_long_int = yes; then
+	  	  	  	  if test "$cross_compiling" = yes; then :
+  :
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <limits.h>
+		 #ifndef LLONG_MAX
+		 # define HALF \
+			  (1LL << (sizeof (long long int) * CHAR_BIT - 2))
+		 # define LLONG_MAX (HALF - 1 + HALF)
+		 #endif
+int
+main ()
+{
+long long int n = 1;
+		 int i;
+		 for (i = 0; ; i++)
+		   {
+		     long long int m = n << i;
+		     if (m >> i != n)
+		       return 1;
+		     if (LLONG_MAX / 2 < m)
+		       break;
+		   }
+		 return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+
+else
+  ac_cv_type_long_long_int=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+	fi
+      fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_type_long_long_int" >&5
+$as_echo "$ac_cv_type_long_long_int" >&6; }
+  if test $ac_cv_type_long_long_int = yes; then
+
+$as_echo "#define HAVE_LONG_LONG_INT 1" >>confdefs.h
+
+  fi
+
+  if test "$ac_cv_type_long_long_int" = no; then
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "Compiler does not support long long int
+See \`config.log' for more details" "$LINENO" 5; }
+  fi
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler supports trailing commas" >&5
+$as_echo_n "checking if the compiler supports trailing commas... " >&6; }
+  trailing_commas=no
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
 int
 main ()
 {
 
-  enum {
+    enum {
-    one,   // one comment
+      one,
-    two,   // two comments
+    };
-    three, // three comments
-  };
-  long long int a = 1;
-  long long unsigned b = 2;
-  printf("a %lld and a %llu", a, b);
-
   ;
   return 0;
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }
+$as_echo "yes" >&6; }; trailing_commas=yes
 else
-  as_fn_error $? "compiler does not work properly - see auto/config.log" "$LINENO" 5
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  if test "$trailing_commas" = no; then
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "Compiler does not support trailing comma in enum
+See \`config.log' for more details" "$LINENO" 5; }
+  fi
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler supports C++ comments" >&5
+$as_echo_n "checking if the compiler supports C++ comments... " >&6; }
+  slash_comments=no
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+// C++ comments?
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }; slash_comments=yes
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  if test "$slash_comments" = no; then
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "Compiler does not support C++ comments
+See \`config.log' for more details" "$LINENO" 5; }
+  fi
+fi
 
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking --enable-fail-if-missing argument" >&5

src/configure.ac

@@ -11,7 +11,7 @@ AC_DEFINE(UNIX)
 AC_PROG_MAKE_SET
 
 dnl Checks for programs.
-AC_PROG_CC_C89		dnl required by almost everything
+AC_PROG_CC_C99		dnl required by almost everything
 AC_PROG_CPP		dnl required by header file checks
 AC_PROGRAM_EGREP	dnl required by AC_EGREP_CPP
 AC_PROG_FGREP		dnl finds working grep -F
@@ -30,23 +30,37 @@ AC_HEADER_STDC
 AC_HEADER_SYS_WAIT
 
 dnl Check that the C99 features that Vim uses are supported:
-dnl - // commands
+if test x"$ac_cv_prog_cc_c99" != xno; then
-dnl - comma after last enum item
+  dnl If the compiler doesn't explicitly support C99, then check
-dnl - "long long int" and "long long unsigned"
+  dnl for the specific features Vim uses
-dnl - flexible array member
+
-AC_MSG_CHECKING(if the compiler can handle Vim code)
+  AC_TYPE_LONG_LONG_INT
-AC_TRY_COMPILE([#include <stdio.h>], [
+  if test "$ac_cv_type_long_long_int" = no; then
-  enum {
+    AC_MSG_FAILURE([Compiler does not support long long int])
-    one,   // one comment
+  fi
-    two,   // two comments
+
-    three, // three comments
+  AC_MSG_CHECKING([if the compiler supports trailing commas])
-  };
+  trailing_commas=no
-  long long int a = 1;
+  AC_TRY_COMPILE([], [
-  long long unsigned b = 2;
+    enum {
-  printf("a %lld and a %llu", a, b);
+      one,
-  ],
+    };],
-AC_MSG_RESULT(yes),
+    [AC_MSG_RESULT(yes); trailing_commas=yes],
-AC_MSG_ERROR([compiler does not work properly - see auto/config.log]))
+    [AC_MSG_RESULT(no)])
+  if test "$trailing_commas" = no; then
+    AC_MSG_FAILURE([Compiler does not support trailing comma in enum])
+  fi
+
+  AC_MSG_CHECKING([if the compiler supports C++ comments])
+  slash_comments=no
+  AC_TRY_COMPILE([],
+    [// C++ comments?],
+    [AC_MSG_RESULT(yes); slash_comments=yes],
+    [AC_MSG_RESULT(no)])
+  if test "$slash_comments" = no; then
+    AC_MSG_FAILURE([Compiler does not support C++ comments])
+  fi
+fi
 
 dnl Check for the flag that fails if stuff are missing.
 

src/version.c

@@ -762,6 +762,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1736,
 /**/
     1735,
 /**/