Squashed 'third_party/glog/' content from commit 9ef754a3023

git-subtree-dir: third_party/glog
git-subtree-split: 9ef754a3023e6fd10f20fe53dfca96dd898182e3

1 files changed, 15 insertions, 0 deletions

diff --git a/m4/namespaces.m4 b/m4/namespaces.m4
new file mode 100644
index 000000000000..d78dbe4cc2e4
--- /dev/null
+++ b/m4/namespaces.m4
@@ -0,0 +1,15 @@
+# Checks whether the compiler implements namespaces
+AC_DEFUN([AC_CXX_NAMESPACES],
+ [AC_CACHE_CHECK(whether the compiler implements namespaces,
+                 ac_cv_cxx_namespaces,
+                 [AC_LANG_SAVE
+                  AC_LANG_CPLUSPLUS
+                  AC_TRY_COMPILE([namespace Outer {
+                                    namespace Inner { int i = 0; }}],
+                                 [using namespace Outer::Inner; return i;],
+                                 ac_cv_cxx_namespaces=yes,
+                                 ac_cv_cxx_namespaces=no)
+                  AC_LANG_RESTORE])
+  if test "$ac_cv_cxx_namespaces" = yes; then
+    AC_DEFINE(HAVE_NAMESPACES, 1, [define if the compiler implements namespaces])
+  fi])