[PATCH, request-for-review] Update CTF's ctf_dict_t detection

[Dodji Seketeli <dodji@redhat.com>]

Hello,

As ctf_dict_t can be an opaque type depending on the version of
ctf-api.h, using AC_CHECK_TYPE won't work to detect it because that
macro invokes sizeof(ctf_dict_t).

With this change, we don't require that ctf_dict_t be fully defined.

	* configure.ac: Use AC_COMPILE_IFELSE to try and compile a code
	snippet that doesn't need that ctf_dict_t be fully defined.

Would this be OK to commit?

Thanks.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>
---
 configure.ac | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/configure.ac b/configure.ac
index d19c2f96..4d214b1c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -334,11 +334,12 @@ if test x$ENABLE_CTF != xno; then
   fi
 
   if test x$LIBCTF = xyes; then
-    dnl Test if struct btf_enum64 is present.
-    AC_CHECK_TYPE([struct ctf_dict_t],
-    		  [HAVE_CTF_DICT_T=yes],
-		  [HAVE_CTF_DICT_T=no],
-		  [#include <ctf-api.h>])
+    dnl Test if struct struct ctf_dict_t is present.
+    AC_LANG(C++)
+    AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#include <ctf-api.h>
+					ctf_dict_t* c;]])],
+		      [HAVE_CTF_DICT_T=yes],
+		      [HAVE_CTF_DICT_T=no])
 
     if test x$HAVE_CTF_DICT_T = xyes; then
       AC_DEFINE([HAVE_CTF_DICT_T], 1, [struct ctf_dict_t is present])
-- 
2.31.1


-- 
		Dodji