configure: disable SAPI if sapi.h cannot be used

for Winstore apps the code is hidden
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

configure.ac

@@ -3266,10 +3266,11 @@ AM_CONDITIONAL([HAVE_HARFBUZZ], [test "${have_harfbuzz}" = "yes"])
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 dnl SAPI (text to Speech renderer for Windows)
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-AC_CHECK_HEADERS(sapi.h, [
+AC_CHECK_TYPES([ISpObjectToken],[
               have_sapi="yes"
-            ],[AC_MSG_WARN([sapi.h not found. Text to Speech renderer for Windows disabled])])
-
+            ],[AC_MSG_WARN([sapi.h not found. Text to Speech renderer for Windows disabled])],
+              [#include <windows.h>
+               #include <sapi.h>])
 AM_CONDITIONAL([HAVE_SAPI], [test "${have_sapi}" = "yes"])
 
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