From 4b7915994fce76c7a81f1d522ceb94558d442de3 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Tue, 2 Nov 2021 23:03:05 +0000
Subject: [PATCH] better test for hyperbolics

---
 configure.ac              |  1 +
 libvips/arithmetic/math.c | 15 ++-------------
 2 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/configure.ac b/configure.ac
index 6855b794..d8632b7f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -394,6 +394,7 @@ AC_CHECK_FUNCS([getcwd gettimeofday getwd memset munmap putenv realpath strcasec
 AC_CHECK_LIB(m,cbrt,[AC_DEFINE(HAVE_CBRT,1,[have cbrt() in libm.])])
 AC_CHECK_LIB(m,hypot,[AC_DEFINE(HAVE_HYPOT,1,[have hypot() in libm.])])
 AC_CHECK_LIB(m,atan2,[AC_DEFINE(HAVE_ATAN2,1,[have atan2() in libm.])])
+AC_CHECK_LIB(m,asinh,[AC_DEFINE(HAVE_ASINH,1,[have asinh() in libm.])])
 
 # have to have these parts of glib ... we need glib 2.15 for gio
 PKG_CHECK_MODULES(REQUIRED, glib-2.0 >= 2.40 gmodule-no-export-2.0 gobject-2.0 gio-2.0)
diff --git a/libvips/arithmetic/math.c b/libvips/arithmetic/math.c
index df37a270..f9fbc3e6 100644
--- a/libvips/arithmetic/math.c
+++ b/libvips/arithmetic/math.c
@@ -129,20 +129,9 @@ vips_math_build( VipsObject *object )
 		g_assert_not_reached(); \
 	} 
 
-/* Inverse hyperbolic functions for old compilers.
- *
- * They were added to the standard in C99 and C++11.
+/* If there's asinh, assume we have the other two as well.
  */
-#if ( \
-  (defined( __cplusplus ) && __cplusplus >= 201103L) || \
-  (defined( __STDC__ ) && __STDC_VERSION__ >= 199901L) \
-)
-  #define HAS_INVERSE_HYPERBOLICS 1
-#else
-  #define HAS_INVERSE_HYPERBOLICS 0
-#endif
-
-#if HAS_INVERSE_HYPERBOLICS
+#if HAVE_ASINH
   #define ASINH( X ) (asinh( X ))
   #define ACOSH( X ) (acosh( X ))
   #define ATANH( X ) (atanh( X ))