Perform Apple SDK tests for Mac ports only.

Fix after changes of r61832: SDK checks should be done for Mac ports only as
they are useless under the other systems and break configure because sw_vers
is Mac-only and unsurprisingly using it results in errors under the other
systems:

/usr/local/src/wx/HEAD/configure: line 18215: sw_vers: command not found
checking if C compiler works with SDK/version options... configure: error: no.
Try a different SDK

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61837 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

configure

@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Id: configure.in 61322 2009-07-05 11:51:53Z VZ .
+# From configure.in Id.
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.61 for wxWidgets 2.9.1.
 #
@@ -18107,9 +18107,11 @@ echo "$as_me: error: ar is needed to build wxWidgets" >&2;}
     fi
 fi
 
+
+if test "$wxUSE_MAC" = 1; then
+
 retest_macosx_linking=no
 
-#if test "$wxUSE_MAC" = 1; then
     if test "x$wxUSE_UNIVERSAL_BINARY" != xno ; then
                         if test "x$wxUSE_UNIVERSAL_BINARY" == xyes; then
             # Implicitly turn on the new --with-macosx-sdk using the default
@@ -18153,7 +18155,6 @@ echo "$as_me: WARNING: Please use --with-macosx-sdk=PATH and --enable-universal_
 echo "$as_me: WARNING: Disabling precompiled headers due to universal binary build." >&2;}
         bk_use_pch=no
     fi
-#fi
 
 if test "x$wxUSE_MACOSX_SDK" = "xno"; then
     wxUSE_MACOSX_SDK=
@@ -18387,7 +18388,7 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 fi
 
-
+fi
 case "${host}" in
 
                 *-*-darwin* )

configure.in

@@ -1042,10 +1042,15 @@ if test "x$SUNCXX" != xyes; then
     fi
 fi
 
+dnl ---------------------------------------------------------------------------
+dnl Mac-specific SDK/architectures checks
+dnl ---------------------------------------------------------------------------
+
+if test "$wxUSE_MAC" = 1; then
+
 retest_macosx_linking=no
 
 dnl Support the old --enable-universal_binary in case anyone was using it.
-#if test "$wxUSE_MAC" = 1; then
     if test "x$wxUSE_UNIVERSAL_BINARY" != xno ; then
         dnl --enable-universal_binary uses a default SDK (currently 10.4u)
         dnl --enable-universal_binary=SDK names a path to an SDK
@@ -1102,7 +1107,6 @@ dnl Support the old --enable-universal_binary in case anyone was using it.
         AC_MSG_WARN([Disabling precompiled headers due to universal binary build.])
         bk_use_pch=no
     fi
-#fi
 
 dnl Set up the Mac OS X SDK.  We do this early so configure tests will occur
 dnl with the SDK in place.
@@ -1225,6 +1229,7 @@ if test "x$retest_macosx_linking" = "xyes"; then
     AC_LANG_POP()
 fi
 
+fi dnl wxUSE_MAC
 
 case "${host}" in