+dnl --------------------------------------------------------------------
+dnl Check for MSVC
+AC_DEFUN([OL_MSVC],
+[AC_REQUIRE_CPP()dnl
+AC_CACHE_CHECK([whether we are using MS Visual C++], ol_cv_msvc,
+[AC_PREPROC_IFELSE([AC_LANG_SOURCE([[
+#ifndef _MSC_VER
+#include <__FOO__/generate_error.h>
+#endif
+]])],[ol_cv_msvc=yes],[ol_cv_msvc=no])])])
+
+dnl --------------------------------------------------------------------
+dnl OpenLDAP version of STDC header check w/ EBCDIC support
+AC_DEFUN([OL_HEADER_STDC],
+[AC_REQUIRE_CPP()dnl
+AC_REQUIRE([OL_CPP_EBCDIC])dnl
+AC_CACHE_CHECK([for ANSI C header files], ol_cv_header_stdc,
+[AC_PREPROC_IFELSE([AC_LANG_SOURCE([[#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <float.h>]])],[ol_cv_header_stdc=yes],[ol_cv_header_stdc=no])
+
+if test $ol_cv_header_stdc = yes; then
+ # SunOS 4.x string.h does not declare mem*, contrary to ANSI.
+AC_EGREP_HEADER(memchr, string.h, , ol_cv_header_stdc=no)
+fi
+
+if test $ol_cv_header_stdc = yes; then
+ # ISC 2.0.2 stdlib.h does not declare free, contrary to ANSI.
+AC_EGREP_HEADER(free, stdlib.h, , ol_cv_header_stdc=no)
+fi
+
+if test $ol_cv_header_stdc = yes; then
+ # /bin/cc in Irix-4.0.5 gets non-ANSI ctype macros unless using -ansi.
+AC_RUN_IFELSE([AC_LANG_SOURCE([[#include <ctype.h>
+#ifndef HAVE_EBCDIC
+# define ISLOWER(c) ('a' <= (c) && (c) <= 'z')
+# define TOUPPER(c) (ISLOWER(c) ? 'A' + ((c) - 'a') : (c))
+#else
+# define ISLOWER(c) (('a' <= (c) && (c) <= 'i') \
+ || ('j' <= (c) && (c) <= 'r') \
+ || ('s' <= (c) && (c) <= 'z'))
+# define TOUPPER(c) (ISLOWER(c) ? ((c) | 0x40) : (c))
+#endif
+#define XOR(e, f) (((e) && !(f)) || (!(e) && (f)))
+int main () { int i; for (i = 0; i < 256; i++)
+if (XOR (islower (i), ISLOWER (i)) || toupper (i) != TOUPPER (i)) exit(2);
+exit (0); }
+]])],[],[ol_cv_header_stdc=no],[:])
+fi])
+if test $ol_cv_header_stdc = yes; then
+ AC_DEFINE(STDC_HEADERS)
+fi
+ac_cv_header_stdc=disable
+])