Fix sparc64 build with -DNO_ASM and reduce compiler warnings.

[cln.git] / m4 / cc.m4

diff --git a/m4/cc.m4 b/m4/cc.m4
index ec6c5e8c3471c0ac48c09300710ff80a217744fe..768dba1d600eae55fb66b7cbbbc54dbd31910099 100644 (file)
--- a/m4/cc.m4
+++ b/m4/cc.m4
@@ -67,3 +67,28 @@ EOF
   fi
   AC_SUBST(ASMFLAGS)
 ])
+
+
+dnl Checks whether the compiler supports __attribute__((flatten)).
+AC_DEFUN([CL_ATTRIBUTE_FLATTEN],[
+AC_REQUIRE([AC_PROG_CXX])
+AC_CACHE_CHECK([whether the compiler supports __attribute__((flatten))], cl_cv_have_attr_flatten, [dnl
+  cat > conftest.cc <<EOF
+void f() __attribute__((flatten));
+EOF
+if AC_TRY_COMMAND(${CXX-g++} $CXXFLAGS -c conftest.cc >/dev/null 2>conftest.stderr)
+then
+  if grep -i "warning" conftest.stderr > /dev/null; then
+    cl_cv_have_attr_flatten=no
+  else
+    cl_cv_have_attr_flatten=yes
+  fi
+else
+  cl_cv_have_attr_flatten=no
+fi
+rm -f conftest*
+])
+if test $cl_cv_have_attr_flatten = yes; then
+  AC_DEFINE(CL_HAVE_ATTRIBUTE_FLATTEN)
+fi
+])