+dnl
+dnl AC_PROG_GNUCPP gathers the path to the cpp that the
+dnl gcc driver calls upon.
+dnl
+dnl Substitutes: GNUCPP and RAWCPP (latter is 'GNUCPP -traditional')
+dnl
+AC_DEFUN(AC_PROG_GNUCPP,
+[AC_CACHE_CHECK([how to invoke GNU cpp directly], ac_cv_gnu_cpp,
+[if test "$HaveGcc" = "YES"; then
+ echo > conftest.c
+ gcc -v -E conftest.c >/dev/null 2>conftest.out
+ # \x5c = backslash
+ echo 'tr/\x5c/\//; /(\S+\/cpp)/ && print "[$]1";' > conftest.pl
+ ac_cv_gnu_cpp="`eval $PerlCmd -n conftest.pl conftest.out`"
+ rm -fr conftest*
+ else
+ # We need to be able to invoke CPP directly, preferably
+ # with input from stdin (mkdependHS and hscpp depend on
+ # this at the moment).
+ # Take a guess at what to use, this probably won't work.
+ echo Warning: GNU cpp not found, using $CPP
+ ac_cv_gnu_cpp = $CPP
+ fi
+])
+GNUCPP=$ac_cv_gnu_cpp
+RAWCPP="$GNUCPP -traditional"
+AC_SUBST(GNUCPP)
+AC_SUBST(RAWCPP)
+])
+
+dnl Small feature test for perl version. Assumes PerlCmd
+dnl contains path to perl binary
+dnl
+AC_DEFUN(AC_CHECK_PERL_VERSION,
+[$PerlCmd -v >conftest.out 2>&1
+if grep "version 4" conftest.out >/dev/null 2>&1; then
+ if grep "Patch level: 35" conftest.out >/dev/null 2>&1; then
+ echo "
+************************************************************************
+Uh-oh...looks like you have Perl 4.035.
+
+Perl version 4.035 has a bug to do with recursion that will bite if
+you run the lit2texi script, when making Info files from
+literate files of various sorts. Either use perl5, the last version of perl4
+(4.036), or an older version (e.g., perl 4.019). Failing that, don't create
+any Info files :-)
+************************************************************************
+"
+ fi
+else
+ if grep "version 5" conftest.out >/dev/null 2>&1; then
+ :
+ else
+ echo "I'm not sure if your version of perl will work,"
+ echo "but it's worth a shot, eh?"
+ fi
+fi
+rm -fr conftest*
+])
+
+dnl ** figure out the alignment restriction of a type
+dnl (required SIZEOF test but AC_CHECK_SIZEOF doesn't call PROVIDE
+dnl so we can't call REQUIRE)
+
+dnl GHC_CHECK_ALIGNMENT(TYPE)
+AC_DEFUN(GHC_CHECK_ALIGNMENT,
+[changequote(<<, >>)dnl
+dnl The name to #define.
+define(<<AC_TYPE_NAME>>, translit(alignment_$1, [a-z *], [A-Z_P]))dnl
+dnl The cache variable name.
+define(<<AC_CV_NAME>>, translit(ac_cv_alignment_$1, [ *], [_p]))dnl
+dnl The name of the corresponding size.
+define(<<AC_CV_SIZEOF_NAME>>, translit(ac_cv_sizeof_$1, [ *], [_p]))dnl
+changequote([, ])dnl
+AC_MSG_CHECKING(alignment of $1)
+AC_CACHE_VAL(AC_CV_NAME,
+[AC_TRY_RUN([
+#include <stdio.h>
+#if HAVE_STDDEF_H
+#include <stddef.h>
+#endif
+#ifndef offsetof
+#define offsetof(ty,field) ((size_t)((char *)&((ty *)0)->field - (char *)(ty *)0))
+#endif
+int
+main()
+{
+ FILE *f=fopen("conftestval", "w");
+ if (!f) exit(1);
+ fprintf(f, "%d\n", offsetof(struct { char c; $1 ty;},ty));
+ exit(0);
+}],
+AC_CV_NAME=`cat conftestval`,
+AC_CV_NAME=$AC_CV_SIZEOF_NAME,
+AC_CV_NAME=$AC_CV_SIZEOF_NAME)])
+AC_MSG_RESULT($AC_CV_NAME)
+AC_DEFINE_UNQUOTED(AC_TYPE_NAME, $AC_CV_NAME)
+AC_PROVIDE($AC_TYPE_NAME)
+undefine([AC_TYPE_NAME])dnl
+undefine([AC_CV_NAME])dnl
+undefine([AC_CV_SIZEOF_NAME])dnl
+])