[test/invalid-matrix] Disable floating point exception.

test/invalid-matrix purposely feeds invalid numbers into cairo, in
order to check its detection of garbage values. In doing so, cairo
raises an Invalid exception, but as this is a direct result of an abuse
of the API we can treat it as expected behaviour and ignore the
exception.

configure.in

@@ -126,7 +126,7 @@ esac
 AC_MSG_RESULT([$solaris_posix_pthread])
 
 # check for GNU-extensions to fenv
-AC_CHECK_HEADER(fenv.h, [AC_CHECK_FUNCS(feenableexcept)])
+AC_CHECK_HEADER(fenv.h, [AC_CHECK_FUNCS(feenableexcept fedisableexcept)])
 
 dnl ===========================================================================
 dnl

test/invalid-matrix.c

@@ -30,6 +30,10 @@
 #define HAVE_INFINITY 1
 #endif
 
+#if HAVE_FEDISABLEEXCEPT
+#include <fenv.h>
+#endif
+
 static cairo_test_draw_function_t draw;
 
 cairo_test_t test = {
@@ -69,6 +73,11 @@ if ((status) == CAIRO_STATUS_SUCCESS) {							\
     return CAIRO_TEST_FAILURE;								\
 }
 
+    /* clear floating point exceptions (added by cairo_test_init()) */
+#if HAVE_FEDISABLEEXCEPT
+    fedisableexcept (FE_INVALID);
+#endif
+
     /* create a bogus matrix and check results of attempted inversion */
     bogus.x0 = bogus.xy = bogus.xx = strtod ("NaN", NULL);
     bogus.y0 = bogus.yx = bogus.yy = bogus.xx;