if a package doesn't happen to include stddef.h before trying to do AC_CHECK_ALIGNOF, the current cross-compile fallback fails with newer gcc.
for example, see the attached generated conftest.c (taken from recent glib versions) where it does: AC_CHECK_TYPE([guint32],,,[typedef unsigned $gint32 guint32;]) AC_CHECK_ALIGNOF([guint32], [AC_INCLUDES_DEFAULT typedef unsigned $gint32 guint32;]) compiling this gcc-4.5+ fails (checked 4.4.7, 4.5.3, 4.6.3, and 4.7.1): $ gcc -O2 conftest.c conftest.c: In function ‘main’: conftest.c:216:12: error: storage size of ‘test_array’ isn’t constant if, however, we happen to pull in the stddef.h from gcc which now includes an offsetof definition itself (which uses a builtin), everything works nicely: $ gcc -O2 conftest.c -DSTDC_HEADERS perhaps one fix would be for AC_CHECK_ALIGNOF to require AC_STDC_HEADERS ? -mike
/* confdefs.h */ #define PACKAGE_NAME "glib" #define PACKAGE_TARNAME "glib" #define PACKAGE_VERSION "2.32.4" #define PACKAGE_STRING "glib 2.32.4" #define PACKAGE_BUGREPORT "http://bugzilla.gnome.org/enter_bug.cgi?product=glib"; #define PACKAGE_URL "" #define GLIB_MAJOR_VERSION 2 #define GLIB_MINOR_VERSION 32 #define GLIB_MICRO_VERSION 4 #define GLIB_INTERFACE_AGE 4 #define GLIB_BINARY_AGE 3204 #define _GNU_SOURCE 1 #define _FILE_OFFSET_BITS 64 #define HAVE_LOCALE_H 1 #define HAVE_LC_MESSAGES 1 #define HAVE_BIND_TEXTDOMAIN_CODESET 1 #define HAVE_GETTEXT 1 #define HAVE_DCGETTEXT 1 #define ENABLE_NLS 1 #define GETTEXT_PACKAGE "glib20" #define GLIB_LOCALE_DIR "/usr/share/locale" #define HAVE_DLFCN_H 1 #define LT_OBJDIR ".libs/" #define HAVE_VPRINTF 1 #define HAVE_ALLOCA_H 1 #define HAVE_ALLOCA 1 #define HAVE_MMAP 1 #define HAVE_POSIX_MEMALIGN 1 #define HAVE_MEMALIGN 1 #define HAVE_VALLOC 1 #define HAVE_FSYNC 1 #define HAVE_PIPE2 1 #define HAVE_ATEXIT 1 #define HAVE_ON_EXIT 1 #define HAVE_TIMEGM 1 #define HAVE_GMTIME_R 1 #define SIZEOF_CHAR 1 #define SIZEOF_SHORT 2 #define SIZEOF_LONG 4 #define SIZEOF_INT 4 #define SIZEOF_VOID_P 4 #define SIZEOF_LONG_LONG 8 #define SIZEOF___INT64 0 #define HAVE_SIG_ATOMIC_T 1 #define HAVE_LONG_LONG_FORMAT 1 #define G_HAVE___INLINE 1 #define G_HAVE___INLINE__ 1 #define G_HAVE_INLINE 1 #define HAVE_DOWHILE_MACROS 1 #define HAVE_DIRENT_H 1 #define HAVE_FLOAT_H 1 #define HAVE_LIMITS_H 1 #define HAVE_PWD_H 1 #define HAVE_GRP_H 1 #define HAVE_SYS_PARAM_H 1 #define HAVE_SYS_POLL_H 1 #define HAVE_SYS_RESOURCE_H 1 #define HAVE_SYS_TIME_H 1 #define HAVE_SYS_TIMES_H 1 #define HAVE_SYS_WAIT_H 1 #define HAVE_UNISTD_H 1 #define HAVE_VALUES_H 1 #define HAVE_SYS_SELECT_H 1 #define HAVE_SYS_TYPES_H 1 #define HAVE_STDINT_H 1 #define HAVE_INTTYPES_H 1 #define HAVE_SCHED_H 1 #define HAVE_MALLOC_H 1 #define HAVE_SYS_VFS_H 1 #define HAVE_SYS_STATFS_H 1 #define HAVE_SYS_STATVFS_H 1 #define HAVE_MNTENT_H 1 #define HAVE_FSTAB_H 1 #define HAVE_SYS_UIO_H 1 #define HAVE_LINUX_MAGIC_H 1 #define HAVE_SYS_PRCTL_H 1 #define HAVE_SYS_MOUNT_H 1 #define HAVE_SYS_SYSCTL_H 1 #define HAVE_XLOCALE_H 1 #define HAVE_STRUCT_STAT_ST_BLKSIZE 1 #define HAVE_STRUCT_STAT_ST_BLOCKS 1 #define HAVE_STRUCT_STATFS_F_BAVAIL 1 #define HAVE_STRUCT_TM_TM_GMTOFF 1 #define HAVE_DIRENT_H 1 #define HAVE_STRUCT_DIRENT_D_TYPE 1 #define HAVE_LANGINFO_CODESET 1 #define HAVE_STDDEF_H 1 #define HAVE_STDLIB_H 1 #define HAVE_STRING_H 1 #define HAVE_SETLOCALE 1 #define SIZEOF_SIZE_T 4 #define HAVE_LSTAT 1 #define HAVE_STRERROR 1 #define HAVE_STRSIGNAL 1 #define HAVE_MEMMOVE 1 #define HAVE_VSNPRINTF 1 #define HAVE_STPCPY 1 #define HAVE_STRCASECMP 1 #define HAVE_STRNCASECMP 1 #define HAVE_POLL 1 #define HAVE_GETCWD 1 #define HAVE_VASPRINTF 1 #define HAVE_SETENV 1 #define HAVE_UNSETENV 1 #define HAVE_GETC_UNLOCKED 1 #define HAVE_READLINK 1 #define HAVE_SYMLINK 1 #define HAVE_MEMMEM 1 #define HAVE_CHOWN 1 #define HAVE_LCHOWN 1 #define HAVE_FCHMOD 1 #define HAVE_FCHOWN 1 #define HAVE_LINK 1 #define HAVE_UTIMES 1 #define HAVE_GETGRGID 1 #define HAVE_GETPWUID 1 #define HAVE_GETMNTENT_R 1 #define HAVE_SETMNTENT 1 #define HAVE_ENDMNTENT 1 #define HAVE_HASMNTOPT 1 #define HAVE_SPLICE 1 #define HAVE_PRLIMIT 1 #define HAVE_STATVFS 1 #define HAVE_STATFS 1 #define USE_STATFS 1 #define HAVE_NEWLOCALE 1 #define HAVE_USELOCALE 1 #define HAVE_STRTOD_L 1 #define HAVE_STRTOLL_L 1 #define HAVE_STRTOULL_L 1 #define HAVE_C99_VSNPRINTF 1 #define HAVE_UNIX98_PRINTF 1 #define HAVE_GETPROTOBYNAME_R 1 #define HAVE_ENDSERVENT 1 #define HAVE_IF_NAMETOINDEX 1 #define HAVE_NETDB_H 1 #define HAVE_ARPA_NAMESER_COMPAT_H 1 #define HAVE_NETLINK 1 #define HAVE_IP_MREQN /**/ #define STATFS_ARGS 2 #define HAVE_GOOD_PRINTF 1 #define HAVE_LONG_LONG 1 #define HAVE_LONG_DOUBLE 1 #define HAVE_WCHAR_T 1 #define HAVE_WINT_T 1 #define HAVE_INTTYPES_H_WITH_UINTMAX 1 #define HAVE_STDINT_H_WITH_UINTMAX 1 #define HAVE_INTMAX_T 1 #define HAVE_SNPRINTF 1 #define HAVE_WCSLEN 1 #define REALLOC_0_WORKS 1 #define HAVE_CODESET 1 #define HAVE_LANGINFO_TIME 1 #define HAVE_LANGINFO_OUTDIGIT 1 #define G_VA_COPY va_copy #define G_VA_COPY_AS_ARRAY 1 #define HAVE_SYS_INOTIFY_H 1 #define HAVE_INOTIFY_INIT1 1 #define HAVE_LIBELF 1 #define HAVE_LIBELF 1 #define HAVE_LIBELF 1 #define HAVE_LIBELF 1 #define HAVE_LOCALTIME_R 1 #define HAVE_GMTIME_R 1 #define HAVE_POSIX_GETPWUID_R 1 #define HAVE_POSIX_GETGRGID_R 1 #define HAVE_PTHREAD_ATTR_SETSTACKSIZE 1 #define HAVE_PTHREAD_CONDATTR_SETCLOCK 1 #define HAVE_CLOCK_GETTIME 1 #define HAVE_FUTEX 1 #define HAVE_EVENTFD 1 /* end confdefs.h. */ #include <stdio.h> #ifdef HAVE_SYS_TYPES_H # include <sys/types.h> #endif #ifdef HAVE_SYS_STAT_H # include <sys/stat.h> #endif #ifdef STDC_HEADERS # include <stdlib.h> # include <stddef.h> #else # ifdef HAVE_STDLIB_H # include <stdlib.h> # endif #endif #ifdef HAVE_STRING_H # if !defined STDC_HEADERS && defined HAVE_MEMORY_H # include <memory.h> # endif # include <string.h> #endif #ifdef HAVE_STRINGS_H # include <strings.h> #endif #ifdef HAVE_INTTYPES_H # include <inttypes.h> #endif #ifdef HAVE_STDINT_H # include <stdint.h> #endif #ifdef HAVE_UNISTD_H # include <unistd.h> #endif typedef unsigned int guint32; #ifndef offsetof # define offsetof(type, member) ((char *) &((type *) 0)->member - (char *) 0) #endif typedef struct { char x; guint32 y; } ac__type_alignof_; int main () { static int test_array [1 - 2 * !(((long int) offsetof (ac__type_alignof_, y)) >= 4)]; test_array [0] = 0 ; return 0; }
