Fix XAA support. Problem noticed by sthen@

driver/xf86-video-mga/configure.ac

@@ -138,6 +138,9 @@ if test "x$XAA" != xno; then
         CFLAGS=$XORG_CFLAGS
         CPPFLAGS="$XORG_CFLAGS"
         AC_CHECK_HEADERS([xaa.h], XAA=yes, XAA=no)
+	if test "x$XAA" = xyes; then
+		AC_DEFINE(USE_XAA, 1, [Build support for xaa])
+	fi
         CFLAGS=$save_CFLAGS
         CPPFLAGS=$save_CPPFLAGS
 fi

driver/xf86-video-mga/src/mga_dri.c

@@ -355,7 +355,7 @@ void MGAGetQuiescence( ScrnInfoPtr pScrn )
       MGAWaitForIdleDMA( pScrn );
 
         /* FIXME what about EXA? */
-#ifdef XAA
+#ifdef USE_XAA
         if (!pMga->Exa && pMga->AccelInfoRec) {
       WAITFIFO( 11 );
       OUTREG( MGAREG_MACCESS, pMga->MAccess );

driver/xf86-video-mga/src/mga_driver.c

@@ -87,7 +87,7 @@
 #include "mga_macros.h"
 #include "mga_maven.h"
 
-#ifdef XAA
+#ifdef HAVE_XAA_H
 #include "xaa.h"
 #endif
 
@@ -2115,7 +2115,7 @@ MGAPreInit(ScrnInfoPtr pScrn, int flags)
 	    }
 	} else {
 #endif
-#ifdef XAA
+#ifdef USE_XAA
 	    if (!xf86LoadSubModule(pScrn, "xaa")) {
 		xf86DrvMsg(pScrn->scrnIndex, X_INFO,
 		           "Falling back to shadowfb\n");
@@ -3765,7 +3765,7 @@ MGACloseScreen(CLOSE_SCREEN_ARGS_DECL)
        pMgaEnt->refCount--;
    }
 
-#ifdef XAA
+#ifdef USE_XAA
     if (pMga->AccelInfoRec)
 	XAADestroyInfoRec(pMga->AccelInfoRec);
 #endif