https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112534
Bruno Haible <bruno at clisp dot org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |bruno at clisp dot org --- Comment #2 from Bruno Haible <bruno at clisp dot org> --- > gcc version 4.8.5 20150623 (Red Hat 4.8.5-44) (GCC) > gcc -std=gnu99 ... > error: unknown type name 'max_align_t' The type 'max_align_t' exists in C11, but not in C99, as can be seen from these uses of gcc 4.8.5: $ cat foo.c #include <stddef.h> max_align_t x; $ gcc -std=c11 -c foo.c $ gcc -std=gnu11 -c foo.c $ gcc -std=c99 -c foo.c foo.c:2:1: error: unknown type name ‘max_align_t’ max_align_t x; ^ $ gcc -std=gnu99 -c foo.c foo.c:2:1: error: unknown type name ‘max_align_t’ max_align_t x; ^ But this occurs in the build tree of gettext-runtime, and this package uses AC_PROG_CC, which adds option -std=gnu11 if supported (this is in GNU Autoconf since version 2.70). Maybe some configure file was built with Autoconf 2.69 and older and thus does not add -std=gnu11 ? Or some other configure in the build tree has determined CC="gcc -std=gnu99", and this setting has been propagated into gettext-runtime, overriding the findings from gettext-runtime/configure ?