No longer try to support non-reentrant Xlib.

diff --git a/configure b/configure
index e5d6224..669a086 100755
--- a/configure
+++ b/configure
@@ -842,7 +842,6 @@
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
   --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
   --without-curses        do not use curses
-  --without-reentrant-x   compile for use with non-reentrant X libraries
   --with-x                use the X Window System
 
 Some influential environment variables:
@@ -1266,12 +1265,6 @@
 
 fi;
 
-# Check whether --with-reentrant-x or --without-reentrant-x was given.
-if test "${with_reentrant_x+set}" = set; then
-  withval="$with_reentrant_x"
-
-fi;
-
 
 if test "x$enable_debug" = "xno"
 then
@@ -10054,54 +10047,38 @@
 fi
 
 
-if test "$have_x" = "yes" -a "$wine_cv_libc_reentrant" != "no"
+if test "$have_x" = "yes"
 then
 echo "$as_me:$LINENO: checking for reentrant X libraries" >&5
 echo $ECHO_N "checking for reentrant X libraries... $ECHO_C" >&6
 if test "${wine_cv_x_reentrant+set}" = set; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
-   if test "x$with_reentrant_x" = "xno"
-    then
-        wine_cv_x_reentrant=no
+  libX11_check=none
+    for dir in "$x_libraries" /usr/lib /usr/local/lib /lib; do
+        if test -r $dir/libX11.so; then
+            libX11_check="-D $dir/libX11.so"
+            break
+        fi
+        if test -r $dir/libX11.a; then
+            libX11_check="$dir/libX11.a"
+            break
+        fi
+    done
+    if test "$libX11_check" != "none"; then
+        if nm $libX11_check | grep $wine_cv_libc_reentrant >/dev/null 2>&1
+        then
+            wine_cv_x_reentrant=yes
+        else
+            wine_cv_x_reentrant=no
+        fi
     else
-	libX11_check=none
-	for dir in "$x_libraries" /usr/lib /usr/local/lib /lib; do
-	    if test -r $dir/libX11.so; then
-		libX11_check="-D $dir/libX11.so"
-		break 1
-	    fi
-	    if test -r $dir/libX11.a; then
-		libX11_check="$dir/libX11.a"
-		break 1
-	    fi
-	done
-	if test "$libX11_check" != "none"; then
-	    if nm $libX11_check | grep $wine_cv_libc_reentrant >/dev/null 2>&1
-	    then
-		wine_cv_x_reentrant=yes
-	    else
-		wine_cv_x_reentrant=no
-	    fi
-	else
-	    wine_cv_x_reentrant=unknown
-	fi
+        wine_cv_x_reentrant=unknown
     fi
 fi
 echo "$as_me:$LINENO: result: $wine_cv_x_reentrant" >&5
 echo "${ECHO_T}$wine_cv_x_reentrant" >&6
-else
-    wine_cv_x_reentrant=no
 fi
-if test "$wine_cv_x_reentrant" = "no"
-then
-
-cat >>confdefs.h <<\_ACEOF
-#define NO_REENTRANT_X11 1
-_ACEOF
-
-fi
-
 
 
 # The Ultrix 4.2 mips builtin alloca declared by alloca.h only works
@@ -13888,6 +13865,13 @@
   echo "*** reentrant version of libc."
 fi
 
+if test "$have_x" = "yes" -a "$wine_cv_x_reentrant" != "yes"
+then
+  echo
+  echo "*** Warning: non-reentrant X11 library detected. Multi-threaded"
+  echo "*** applications won't work properly. You should upgrade your X11 library."
+fi
+
 if test "$wine_cv_opengl_version_OK" = "no"
 then
   echo
diff --git a/configure.ac b/configure.ac
index e565d68..04ea55b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -19,7 +19,6 @@
 AC_ARG_ENABLE(trace, AC_HELP_STRING([--disable-trace],[compile out TRACE messages]))
 AC_ARG_ENABLE(opengl,AC_HELP_STRING([--enable-opengl],[force usage of OpenGL even if the latter is thread-safe via pthread]))
 AC_ARG_WITH(curses,     AC_HELP_STRING([--without-curses],[do not use curses]))
-AC_ARG_WITH(reentrant-x,AC_HELP_STRING([--without-reentrant-x],[compile for use with non-reentrant X libraries]))
 
 AC_SUBST(OPTIONS)
 if test "x$enable_debug" = "xno"
@@ -833,47 +832,33 @@
 dnl **** Check for reentrant X libraries ****
 dnl
 dnl This may fail to determine whether X libraries are reentrant if
-dnl AC_PATH_XTRA does not set x_libraries. In this case manual configuration
-dnl is possible with the --without-reentrant-x option.
+dnl AC_PATH_XTRA does not set x_libraries.
 
-if test "$have_x" = "yes" -a "$wine_cv_libc_reentrant" != "no"
+if test "$have_x" = "yes"
 then
 AC_CACHE_CHECK( [for reentrant X libraries], wine_cv_x_reentrant,
-  [ if test "x$with_reentrant_x" = "xno" 
-    then
-        wine_cv_x_reentrant=no
+    [libX11_check=none
+    for dir in "$x_libraries" /usr/lib /usr/local/lib /lib; do
+        if test -r $dir/libX11.so; then
+            libX11_check="-D $dir/libX11.so"
+            break
+        fi
+        if test -r $dir/libX11.a; then
+            libX11_check="$dir/libX11.a"
+            break
+        fi
+    done
+    if test "$libX11_check" != "none"; then
+        if nm $libX11_check | grep $wine_cv_libc_reentrant >/dev/null 2>&1
+        then
+            wine_cv_x_reentrant=yes
+        else
+            wine_cv_x_reentrant=no
+        fi
     else
-	libX11_check=none
-	for dir in "$x_libraries" /usr/lib /usr/local/lib /lib; do
-	    if test -r $dir/libX11.so; then
-		libX11_check="-D $dir/libX11.so"
-		break 1
-	    fi
-	    if test -r $dir/libX11.a; then
-		libX11_check="$dir/libX11.a"
-		break 1
-	    fi
-	done
-	if test "$libX11_check" != "none"; then
-	    if nm $libX11_check | grep $wine_cv_libc_reentrant >/dev/null 2>&1
-	    then
-		wine_cv_x_reentrant=yes
-	    else
-		wine_cv_x_reentrant=no
-	    fi
-	else
-	    wine_cv_x_reentrant=unknown
-	fi
-    fi ] )
-else
-    wine_cv_x_reentrant=no
+        wine_cv_x_reentrant=unknown
+    fi])
 fi
-if test "$wine_cv_x_reentrant" = "no"
-then
-  AC_DEFINE(NO_REENTRANT_X11, 1,
-            [Define if X libraries are not reentrant (compiled without -D_REENTRANT)])
-fi
-
 
 dnl **** Check for functions ****
 
@@ -1439,6 +1424,13 @@
   echo "*** reentrant version of libc."
 fi
 
+if test "$have_x" = "yes" -a "$wine_cv_x_reentrant" != "yes"
+then
+  echo
+  echo "*** Warning: non-reentrant X11 library detected. Multi-threaded"
+  echo "*** applications won't work properly. You should upgrade your X11 library."
+fi
+
 if test "$wine_cv_opengl_version_OK" = "no"
 then
   echo
diff --git a/include/config.h.in b/include/config.h.in
index a77688e..bee5c70 100644
--- a/include/config.h.in
+++ b/include/config.h.in
@@ -575,9 +575,6 @@
 /* Define to disable all debug messages. */
 #undef NO_DEBUG_MSGS
 
-/* Define if X libraries are not reentrant (compiled without -D_REENTRANT) */
-#undef NO_REENTRANT_X11
-
 /* Define to disable trace messages. */
 #undef NO_TRACE_MSGS