From c023e2248275d360ee1d0d26552c10b43cd13272 Mon Sep 17 00:00:00 2001
From: Dominik Vogt <vogt@linux.vnet.ibm.com>
Date: Tue, 11 Nov 2014 13:55:22 +0100
Subject: [PATCH] Detect compiler's _Complex support with a configure check.

This is needed in types.c to initialise the ffi_type_complex_... structs.
---
 configure.ac |  9 +++++++++
 src/types.c  | 21 ++++++++++++++++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 4a44bff..cb44dbf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -363,6 +363,15 @@ fi
 AC_SUBST(HAVE_LONG_DOUBLE)
 AC_SUBST(HAVE_LONG_DOUBLE_VARIANT)
 
+# detect c99 complex type support
+AH_TEMPLATE([HAVE_COMPLEX_TYPES],[Compiler supports C99 complex types])
+AC_MSG_CHECKING([whether compiler supports C99 complex types])
+AC_TRY_COMPILE(,
+    [float _Complex cf;],
+    AC_DEFINE(HAVE_COMPLEX_TYPES)
+    AC_MSG_RESULT(yes),
+    AC_MSG_RESULT([no[,] guess their size and alignment]))
+
 AC_C_BIGENDIAN
 
 GCC_AS_CFI_PSEUDO_OP
diff --git a/src/types.c b/src/types.c
index ef4f151..e16153b 100644
--- a/src/types.c
+++ b/src/types.c
@@ -44,13 +44,14 @@ maybe_const ffi_type ffi_type_##name = {	\
   id, NULL					\
 }
 
+#ifdef HAVE_COMPLEX_TYPES
 #define FFI_COMPLEX_TYPEDEF(name, type, maybe_const)	\
 static ffi_type *ffi_elements_complex_##name [2] = {	\
 	(ffi_type *)(&ffi_type_##name), NULL		\
 };							\
 struct struct_align_complex_##name {			\
   char c;						\
-  _Complex type x;					\
+  type _Complex x;					\
 };							\
 maybe_const ffi_type ffi_type_complex_##name = {	\
   sizeof(_Complex type),				\
@@ -58,6 +59,24 @@ maybe_const ffi_type ffi_type_complex_##name = {	\
   FFI_TYPE_COMPLEX,					\
   (ffi_type **)ffi_elements_complex_##name		\
 }
+#else
+/* Bogus definition for compilers without C99 complex support.  */
+#define FFI_COMPLEX_TYPEDEF(name, type, maybe_const)	\
+static ffi_type *ffi_elements_complex_##name [2] = {	\
+	(ffi_type *)(&ffi_type_##name), NULL		\
+};							\
+struct struct_align_complex_##name {			\
+  char c;						\
+  type x;						\
+  type y;						\
+};							\
+maybe_const ffi_type ffi_type_complex_##name = {	\
+  2 * sizeof(type),					\
+  offsetof(struct struct_align_complex_##name, x),	\
+  FFI_TYPE_COMPLEX,					\
+  (ffi_type **)ffi_elements_complex_##name		\
+}
+#endif
 
 /* Size and alignment are fake here. They must not be 0. */
 const ffi_type ffi_type_void = {
-- 
1.8.4.2