Revert "Tidied up config.h.in to remove redundant guard"

This reverts commit a5247cfd2a63ac4ef4820a61d43af0fb10f722ae.

1 files changed, 21 insertions, 0 deletions

diff --git a/entityx/config.h.in b/entityx/config.h.in
index f57794e..934fadc 100644
--- a/entityx/config.h.in
+++ b/entityx/config.h.in
@@ -5,6 +5,8 @@
 #cmakedefine ENTITYX_INSTALLED_PYTHON_PACKAGE_DIR "@ENTITYX_INSTALLED_PYTHON_PACKAGE_DIR@"
 #cmakedefine ENTITYX_NEED_GET_POINTER_SHARED_PTR_SPECIALIZATION "@ENTITYX_NEED_GET_POINTER_SHARED_PTR_SPECIALIZATION@"
 
+#define ENTITYX_HAVE_STD_SHARED_PTR 1
+
 #include <stdint.h>
 #include "entityx/config.h"
 
@@ -12,8 +14,16 @@ namespace entityx {
 
 static const uint64_t MAX_COMPONENTS = ENTITYX_MAX_COMPONENTS;
 
+}  // namespace entityx
+
+
+// Which shared_ptr implementation should we use?
+#if (ENTITYX_HAVE_STD_SHARED_PTR)
+
 #include <memory>
 
+namespace entityx {
+
 template <typename T>
 using ptr = std::shared_ptr<T>;
 template <typename T>
@@ -25,6 +35,17 @@ ptr<U> static_pointer_cast(const ptr<T> &ptr) {
 template <typename T>
 using enable_shared_from_this = std::enable_shared_from_this<T>;
 
+}  // namespace entityx
+
+#else
+
+#warning "Don't have a std shared_ptr implementation to use"
+
+#endif
+
+
+namespace entityx {
+
 template <typename T>
 bool operator == (const weak_ptr<T> &a, const weak_ptr<T> &b) {
   return a.lock() == b.lock();