diff --git a/CMakeLists.txt b/CMakeLists.txt
index cae3e12a1..57c5b552a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -58,7 +58,7 @@ set(SDL_INTERFACE_AGE 1)
 set(SDL_BINARY_AGE 15)
 set(SDL_VERSION "${SDL_MAJOR_VERSION}.${SDL_MINOR_VERSION}.${SDL_MICRO_VERSION}")
 # the following should match the versions in Xcode project file:
-set(DYLIB_CURRENT_VERSION 15.0.0)
+set(DYLIB_CURRENT_VERSION 15.1.0)
 set(DYLIB_COMPATIBILITY_VERSION 1.0.0)
 
 # Set defaults preventing destination file conflicts
diff --git a/configure b/configure
index f173c8c90..eb67bd8b7 100755
--- a/configure
+++ b/configure
@@ -20123,8 +20123,34 @@ else
   $as_echo_n "(cached) " >&6
 else
   # One or both of the vars are not set, and there is no cached value.
-ac_x_includes=no ac_x_libraries=no
-rm -f -r conftest.dir
+ac_x_includes=no
+ac_x_libraries=no
+# Do we need to do anything special at all?
+ac_save_LIBS=$LIBS
+LIBS="-lX11 $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <X11/Xlib.h>
+int
+main ()
+{
+XrmInitialize ()
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  # We can compile and link X programs with no special options.
+  ac_x_includes=
+  ac_x_libraries=
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS="$ac_save_LIBS"
+# If that didn't work, only try xmkmf and filesystem searches
+# for native compilation.
+if test x"$ac_x_includes" = xno && test "$cross_compiling" = no; then :
+  rm -f -r conftest.dir
 if mkdir conftest.dir; then
   cd conftest.dir
   cat >Imakefile <<'_ACEOF'
@@ -20163,7 +20189,7 @@ _ACEOF
   rm -f -r conftest.dir
 fi
 
-# Standard set of common directories for X headers.
+  # Standard set of common directories for X headers.
 # Check X11 before X11Rn because it is often a symlink to the current release.
 ac_x_header_dirs='
 /usr/X11/include
@@ -20190,6 +20216,8 @@ ac_x_header_dirs='
 /usr/local/include/X11R5
 /usr/local/include/X11R4
 
+/opt/X11/include
+
 /usr/X386/include
 /usr/x386/include
 /usr/XFree86/include/X11
@@ -20263,15 +20291,17 @@ rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 fi # $ac_x_libraries = no
 
+fi
+# Record the results.
 case $ac_x_includes,$ac_x_libraries in #(
-  no,* | *,no | *\'*)
+  no,* | *,no | *\'*) :
     # Didn't find X, or a directory has "'" in its name.
-    ac_cv_have_x="have_x=no";; #(
-  *)
+    ac_cv_have_x="have_x=no" ;; #(
+  *) :
     # Record where we found X for the cache.
     ac_cv_have_x="have_x=yes\
 	ac_x_includes='$ac_x_includes'\
-	ac_x_libraries='$ac_x_libraries'"
+	ac_x_libraries='$ac_x_libraries'" ;;
 esac
 fi
 ;; #(
diff --git a/test/configure b/test/configure
index 021e6b9e4..dbb1c692b 100755
--- a/test/configure
+++ b/test/configure
@@ -3603,8 +3603,34 @@ else
   $as_echo_n "(cached) " >&6
 else
   # One or both of the vars are not set, and there is no cached value.
-ac_x_includes=no ac_x_libraries=no
-rm -f -r conftest.dir
+ac_x_includes=no
+ac_x_libraries=no
+# Do we need to do anything special at all?
+ac_save_LIBS=$LIBS
+LIBS="-lX11 $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <X11/Xlib.h>
+int
+main ()
+{
+XrmInitialize ()
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  # We can compile and link X programs with no special options.
+  ac_x_includes=
+  ac_x_libraries=
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS="$ac_save_LIBS"
+# If that didn't work, only try xmkmf and filesystem searches
+# for native compilation.
+if test x"$ac_x_includes" = xno && test "$cross_compiling" = no; then :
+  rm -f -r conftest.dir
 if mkdir conftest.dir; then
   cd conftest.dir
   cat >Imakefile <<'_ACEOF'
@@ -3643,7 +3669,7 @@ _ACEOF
   rm -f -r conftest.dir
 fi
 
-# Standard set of common directories for X headers.
+  # Standard set of common directories for X headers.
 # Check X11 before X11Rn because it is often a symlink to the current release.
 ac_x_header_dirs='
 /usr/X11/include
@@ -3670,6 +3696,8 @@ ac_x_header_dirs='
 /usr/local/include/X11R5
 /usr/local/include/X11R4
 
+/opt/X11/include
+
 /usr/X386/include
 /usr/x386/include
 /usr/XFree86/include/X11
@@ -3743,15 +3771,17 @@ rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 fi # $ac_x_libraries = no
 
+fi
+# Record the results.
 case $ac_x_includes,$ac_x_libraries in #(
-  no,* | *,no | *\'*)
+  no,* | *,no | *\'*) :
     # Didn't find X, or a directory has "'" in its name.
-    ac_cv_have_x="have_x=no";; #(
-  *)
+    ac_cv_have_x="have_x=no" ;; #(
+  *) :
     # Record where we found X for the cache.
     ac_cv_have_x="have_x=yes\
 	ac_x_includes='$ac_x_includes'\
-	ac_x_libraries='$ac_x_libraries'"
+	ac_x_libraries='$ac_x_libraries'" ;;
 esac
 fi
 ;; #(