--- a/configure.in
+++ b/configure.in
@@ -2398,23 +2398,51 @@ if test -z "$COMPILE_ENVIRONMENT"; then
     SKIP_COMPILER_CHECKS=1
     SKIP_LIBRARY_CHECKS=1
 fi
 
 MOZ_COMPILER_OPTS
 if test -z "$SKIP_COMPILER_CHECKS"; then
 dnl Checks for typedefs, structures, and compiler characteristics.
 dnl ========================================================
-AC_LANG_C
 AC_HEADER_STDC
 AC_C_CONST
 AC_TYPE_MODE_T
 AC_TYPE_OFF_T
 AC_TYPE_PID_T
 AC_TYPE_SIZE_T
+AC_LANG_CPLUSPLUS
+AC_MSG_CHECKING(for __stdcall)
+AC_CACHE_VAL(ac_cv___stdcall,
+ [AC_TRY_COMPILE([template <typename Method> struct foo;
+                  template <> struct foo<void (*)()> {};
+                  template <> struct foo<void (__stdcall*)()> {};],
+                 [],
+                 [ac_cv___stdcall=true],
+                 [ac_cv___stdcall=false])])
+if test "$ac_cv___stdcall" = true ; then
+  AC_DEFINE(HAVE_STDCALL)
+  AC_MSG_RESULT(yes)
+else
+  AC_MSG_RESULT(no)
+fi
+AC_LANG_C
+AC_MSG_CHECKING(for ssize_t)
+AC_CACHE_VAL(ac_cv_type_ssize_t,
+ [AC_TRY_COMPILE([#include <stdio.h>
+                  #include <sys/types.h>],
+                 [ssize_t foo = 0;],
+                 [ac_cv_type_ssize_t=true],
+                 [ac_cv_type_ssize_t=false])])
+if test "$ac_cv_type_ssize_t" = true ; then
+  AC_DEFINE(HAVE_SSIZE_T)
+  AC_MSG_RESULT(yes)
+else
+  AC_MSG_RESULT(no)
+fi
 AC_STRUCT_ST_BLKSIZE
 AC_MSG_CHECKING(for siginfo_t)
 AC_CACHE_VAL(ac_cv_siginfo_t,
  [AC_TRY_COMPILE([#define _POSIX_C_SOURCE 199506L
                   #include <signal.h>],
                  [siginfo_t* info;],
                  [ac_cv_siginfo_t=true],
                  [ac_cv_siginfo_t=false])])