m4 how to detect if you're compiling for x86?

Question

(ps when i say x86 i also mean x86_64) i'm working on a project that may be compiled for several different platforms, and i have some x86-specific files that should only be added when i'm compiling against x86 (as opposed to ARM or anything else)

basically looking for something like

IS_X86([
    dnl compiling for x86
], [
    dnl compiling for something other than x86
])

so.. how do i detect if i'm compiling for x86 in m4?

Answer 1

Edit: per the comments, this is apparently a GNU Autoconf solution, not a pure M4 solution (personally i barely know M4 and barely know Autoconf, i didn't even know this was autoconf-specific code)

here's what i came up with in the end.. seems to work, so unless anyone has a better suggestion,

dnl
dnl PHP_CHECK_X86_TARGET
dnl
dnl check if we're compiling for x86/x86_64
dnl
AC_DEFUN([PHP_CHECK_X86_TARGET], [
  AC_CACHE_CHECK([for x86 target],ac_cv_target_x86,[
  AC_RUN_IFELSE([AC_LANG_SOURCE([[
int main(void) {
#if defined(__x86_64__) || defined(__i386__)
    return 0;
#else
    return 1;
#endif
}
]])],[
  ac_cv_target_x86=yes
],[
  ac_cv_target_x86=no
],[
  ac_cv_target_x86=no
])])
])


dnl
dnl PHP_CHECK_WINDOWS_TARGET
dnl
dnl check if we're compiling for windows
dnl
AC_DEFUN([PHP_CHECK_WINDOWS_TARGET], [
  AC_CACHE_CHECK([for windows target],ac_cv_target_windows,[
  AC_RUN_IFELSE([AC_LANG_SOURCE([[
int main(void) {
#if defined(_WIN32)
    return 0;
#else
    return 1;
#endif
}
]])],[
  ac_cv_target_windows=yes
],[
  ac_cv_target_windows=no
],[
  ac_cv_target_windows=no
])])
])


dnl
dnl PHP_CHECK_UNIX_TARGET
dnl
dnl check if we're compiling for a unix-ish target
dnl
AC_DEFUN([PHP_CHECK_UNIX_TARGET], [
  AC_CACHE_CHECK([for unix-ish target],ac_cv_target_unix,[
  AC_RUN_IFELSE([AC_LANG_SOURCE([[
int main(void) {
#if defined(unix) || defined(__unix) || defined(__unix__)
    return 0;
#else
    return 1;
#endif
}
]])],[
  ac_cv_target_unix=yes
],[
  ac_cv_target_unix=no
],[
  ac_cv_target_unix=no
])])
])