diff options
Diffstat (limited to 'm4')
| -rw-r--r-- | m4/attributes.m4 | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/m4/attributes.m4 b/m4/attributes.m4 index 55f34c9f7..c46715d0e 100644 --- a/m4/attributes.m4 +++ b/m4/attributes.m4 @@ -322,3 +322,23 @@ AC_DEFUN([CC_ATTRIBUTE_ALIGNED], [ [Define the highest alignment supported]) fi ]) + +AC_DEFUN([CC_ATTRIBUTE_PACKED], [ + AC_REQUIRE([CC_CHECK_WERROR]) + AC_CACHE_CHECK([if $CC supports __attribute__((packed))], + [cc_cv_attribute_packed], + [ac_save_CFLAGS="$CFLAGS" + CFLAGS="$CFLAGS $cc_cv_werror" + AC_COMPILE_IFELSE([struct { char a; short b; int c; } __attribute__((packed)) foo;], + [cc_cv_attribute_packed=yes], + [cc_cv_attribute_packed=no]) + CFLAGS="$ac_save_CFLAGS" + ]) + + if test x$cc_cv_attribute_packed = xyes; then + AC_DEFINE([SUPPORT_ATTRIBUTE_PACKED], 1, [Define this if the compiler supports __attribute__((packed))]) + ifelse([$1], , [:], [$1]) + else + ifelse([$2], , [:], [$2]) + fi +]) |