Ruby

# posix_memalign(memptr, alignment, size) implemented for OpenBSD 4.8 doesn't work if alignment > MALLOC_PAGESIZE.

# [ruby-core:42158] https://bugs.ruby-lang.org/issues/5901

# OpenBSD 5.2 fixed the problem. (src/lib/libc/stdlib/malloc.c:1.142)

# MirOS #10semel has the problem but fixed in the repository. (src/lib/libc/stdlib/malloc.c:1.9)

AS_CASE(["$target_os"],

[openbsd*|mirbsd*], [

AC_CACHE_CHECK(for heap align log on openbsd, rb_cv_page_size_log,

[rb_cv_page_size_log=no

for page_log in 12 13; do

AC_TRY_RUN([

#include <math.h>

#include <unistd.h>

int

main() {

if ((int)log2((double)sysconf(_SC_PAGESIZE)) != $page_log) return 1;

return 0;

}

],

rb_cv_page_size_log="$page_log"; break)

done])

AS_IF([test $rb_cv_page_size_log != no], [

AC_DEFINE_UNQUOTED(HEAP_ALIGN_LOG, $rb_cv_page_size_log)

], [

AC_DEFINE_UNQUOTED(HEAP_ALIGN_LOG, 12)

])

])

#ifndef HEAP_PAGE_ALIGN_LOG

#endif