Add STDC FENV_ACCESS ON pragma

This is required by the C99 standard, even though it's not
needed by the compilers we support.

src/cairo-compiler-private.h

@@ -153,6 +153,30 @@
 #define __attribute__(x)
 #endif
 
+#if defined(__clang__)
+#  if __clang_major__ >= 12
+#    define CAIRO_FENV_ACCESS_ON _Pragma ("STDC FENV_ACCESS ON")
+#  else
+#    define CAIRO_FENV_ACCESS_ON
+#  endif
+#elif defined(__GNUC__)
+   /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118838 */
+#  if __GNUC__ >= 16
+     /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=34678 */
+#    define CAIRO_FENV_ACCESS_ON \
+       _Pragma ("GCC diagnostic push") \
+       _Pragma ("GCC diagnostic ignored \"-Wunknown-pragmas\"") \
+       _Pragma ("STDC FENV_ACCESS ON") \
+       _Pragma ("GCC diagnostic pop")
+#  else
+#    define CAIRO_FENV_ACCESS_ON
+#  endif
+#elif defined(_MSC_VER)
+#  define CAIRO_FENV_ACCESS_ON __pragma (fenv_access (on))
+#else
+#  define CAIRO_FENV_ACCESS_ON _Pragma ("STDC FENV_ACCESS ON")
+#endif
+
 #if (defined(__WIN32__) && !defined(__WINE__)) || defined(_MSC_VER)
 #define access _access
 #ifndef R_OK

test/cairo-test.c

@@ -83,6 +83,8 @@
 #define alarm(X);
 #endif
 
+CAIRO_FENV_ACCESS_ON
+
 static const cairo_user_data_key_t _cairo_test_context_key;
 
 static void

test/invalid-matrix.c

@@ -33,6 +33,8 @@
 #define INFINITY HUGE_VAL
 #endif
 
+CAIRO_FENV_ACCESS_ON
+
 static cairo_test_status_t
 draw (cairo_t *cr, int width, int height)
 {