diff --git a/configure.ac b/configure.ac
index 7f0c0fcc0b..47f3d622f1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -638,14 +638,6 @@ AH_TOP([
 ])
 AH_BOTTOM([
 
-#if !HAVE_DECL__CONFIGTHREADLOCALE
-#define NO_PER_THREAD_LOCALE 1
-#undef HAVE__CONFIGTHREADLOCALE
-#else
-#undef NO_PER_THREAD_LOCALE
-#define HAVE__CONFIGTHREADLOCALE 1
-#endif
-
 #ifndef HAVE_RES_INIT
 #define res_init() (0)
 #endif
@@ -926,7 +918,7 @@ AC_PROG_GCC_TRADITIONAL
 AC_FUNC_VPRINTF
 AC_CHECK_FUNCS([ether_ntoa setpriority sched_setscheduler strlcpy strlcat strcasestr strcasecmp sigaction getutent setutent getisax strdup _strdup strdupa _strdupa daemon stat64 putenv setenv unsetenv res_init strtoull localtime localtime_r gmtime gmtime_r uselocale _configthreadlocale])
 
-AC_CHECK_DECLS([_fpreset, fpreset, _configthreadlocale],
+AC_CHECK_DECLS([_fpreset, fpreset],
     [],[],[[
 #include <stdio.h>
 #if HAVE_SYS_TYPES_H
@@ -973,12 +965,6 @@ AC_CHECK_DECLS([_fpreset, fpreset, _configthreadlocale],
 #ifdef HAVE_MATH_H
 #include <math.h>
 #endif
-#ifdef HAVE_LOCALE_H
-#include <locale.h>
-#endif
-#ifdef HAVE_XLOCALE_H
-#include <xlocale.h>
-#endif
 ]])
 
 dnl Checks for typedefs, structures, and compiler characteristics.
diff --git a/lib/boinc_win.h b/lib/boinc_win.h
index 58e516a46f..0260298cb1 100644
--- a/lib/boinc_win.h
+++ b/lib/boinc_win.h
@@ -96,8 +96,6 @@
 #define HAVE_DECL__FPRESET 1
 #define HAVE_DECL___CPUID 1
 #define HAVE_MSVCRT 1
-#undef NO_PER_THREAD_LOCALE
-#define HAVE_DECL__CONFIGTHREADLOCALE 1
 #define HAVE__CONFIGTHREADLOCALE 1
 #define HAVE_DECL___CPUID 1