configure: test for large page sizes

Intended to fix PPC64 builds.

racket/src/configure

@@ -3114,6 +3114,7 @@ enable_strip_by_default=yes
 use_flag_pthread=yes
 use_flag_posix_pthread=no
 skip_iconv_check=no
+check_page_size=yes
 
 ###### OSKit stuff #######
 
@@ -5475,6 +5476,38 @@ $as_echo "#define HAVE_MMAP_MPROTECT 1" >>confdefs.h
   fi
 fi
 
+if test "${check_page_size}" = "yes" ; then
+   msg="for large page size"
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking $msg" >&5
+$as_echo_n "checking $msg... " >&6; }
+  if test "$cross_compiling" = yes; then :
+  use_large_page_size=no
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+     #include <unistd.h>
+     int main() {
+      return !(getpagesize() > (1 << 14));
+     }
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+  use_large_page_size=yes
+else
+  use_large_page_size=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $use_large_page_size" >&5
+$as_echo "$use_large_page_size" >&6; }
+  if test "${use_large_page_size}" = "yes" ; then
+
+$as_echo "#define MZ_USE_LARGE_PAGE_SIZE 1" >>confdefs.h
+
+  fi
+fi
+
 if test "${enable_backtrace}" = "yes" ; then
   GC2OPTIONS="$GC2OPTIONS -DMZ_GC_BACKTRACE"
 fi

racket/src/racket/configure.ac

@@ -415,6 +415,7 @@ enable_strip_by_default=yes
 use_flag_pthread=yes
 use_flag_posix_pthread=no
 skip_iconv_check=no
+check_page_size=yes
 
 ###### OSKit stuff #######
 
@@ -1082,6 +1083,20 @@ if test "${check_for_mprotect}" = "yes" ; then
   fi
 fi
 
+if test "${check_page_size}" = "yes" ; then
+  [ msg="for large page size" ]
+  AC_MSG_CHECKING($msg)
+  AC_TRY_RUN(
+[     #include <unistd.h>]
+     int main() {
+      return !(getpagesize() > (1 << 14));
+     }, use_large_page_size=yes, use_large_page_size=no, use_large_page_size=no)
+  AC_MSG_RESULT($use_large_page_size)
+  if test "${use_large_page_size}" = "yes" ; then
+     AC_DEFINE(MZ_USE_LARGE_PAGE_SIZE,1,[Use large page size])
+  fi
+fi
+
 if test "${enable_backtrace}" = "yes" ; then
   GC2OPTIONS="$GC2OPTIONS -DMZ_GC_BACKTRACE"
 fi

racket/src/racket/gc2/gc2_obj.h

@@ -3,7 +3,7 @@
 
 #if defined(MZ_PRECISE_GC) && !defined(USE_COMPACT_3M_GC)
 
-#ifdef _WIN32
+#if defined(_WIN32) || defined(MZ_USE_LARGE_PAGE_SIZE)
 # define LOG_APAGE_SIZE 16
 #else
 # define LOG_APAGE_SIZE 14

racket/src/racket/mzconfig.h.in

@@ -65,6 +65,9 @@ typedef unsigned long uintptr_t;
 /* When mmap() and mprotect() are available: */
 #undef HAVE_MMAP_MPROTECT
 
+/* To enable 2^16 page size instead of 2^14: */
+#undef MZ_USE_LARGE_PAGE_SIZE
+
 /* Enable futures: */
 #undef MZ_USE_FUTURES