math: add LDBL_CLASSIFY_COMPAT support

If a platform does not define "long-double-fcts = yes" in its
Makefiles and it does define __NO_LONG_DOUBLE_MATH in its installed
headers, it will currently create exported symbols for __finitel,
__isinfl, and __isnanl that can't be reached from userspace by
correct use of the finite(), isinf(), or isnan() macros in <math.h>.

To avoid this situation, by default for such platforms we now no
longer export these symbols, thus causing appropriate link-time
errors.  However, for platforms that previously exported these
symbols, we continue to do so as compat symbols; this is enabled
by adding LDBL_CLASSIFY_COMPAT to math_private.h for the platform.

For tile, remove the now-unnecessary exports of those functions from
libc and libm.

1 files changed, 10 insertions, 0 deletions

diff --git a/sysdeps/sh/math_private.h b/sysdeps/sh/math_private.h
new file mode 100644
index 0000000000..d13f2d49d3
--- /dev/null
+++ b/sysdeps/sh/math_private.h
@@ -0,0 +1,10 @@
+#ifndef SH_MATH_PRIVATE_H
+#define SH_MATH_PRIVATE_H 1
+
+/* Enable __finitel, __isinfl, and __isnanl for binary compatibility
+   when built without long double support. */
+#define LDBL_CLASSIFY_COMPAT 1
+
+#include_next <math_private.h>
+
+#endif