diff --git a/doc/build.py b/doc/build.py
index 2506e45a..da9bc774 100755
--- a/doc/build.py
+++ b/doc/build.py
@@ -89,7 +89,9 @@ def build_docs(version='dev', **kwargs):
                           FMT_USE_VARIADIC_TEMPLATES=1 \
                           FMT_USE_RVALUE_REFERENCES=1 \
                           FMT_USE_USER_DEFINED_LITERALS=1 \
-                          FMT_API=
+                          FMT_API= \
+                          FMT_BEGIN_NAMESPACE=namespace fmt { \
+                          FMT_END_NAMESPACE=}
       EXCLUDE_SYMBOLS   = fmt::internal::* StringValue write_str
     '''.format(include_dir, doxyxml_dir).encode('UTF-8'))
   if p.returncode != 0:
diff --git a/include/fmt/core.h b/include/fmt/core.h
index f497e79d..8580cc93 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -133,14 +133,16 @@
 # define FMT_DTOR_NOEXCEPT FMT_NOEXCEPT
 #endif
 
-#if FMT_HAS_FEATURE(cxx_inline_namespaces) || FMT_MSC_VER >= 1900
-# define FMT_INLINE_NAMESPACE inline namespace
-# define FMT_END_NAMESPACE }}
-#else
-# define FMT_INLINE_NAMESPACE namespace
-# define FMT_END_NAMESPACE } using namespace v5; }
+#ifndef FMT_BEGIN_NAMESPACE
+# if FMT_HAS_FEATURE(cxx_inline_namespaces) || FMT_MSC_VER >= 1900
+#  define FMT_INLINE_NAMESPACE inline namespace
+#  define FMT_END_NAMESPACE }}
+# else
+#  define FMT_INLINE_NAMESPACE namespace
+#  define FMT_END_NAMESPACE } using namespace v5; }
+# endif
+# define FMT_BEGIN_NAMESPACE namespace fmt { FMT_INLINE_NAMESPACE v5 {
 #endif
-#define FMT_BEGIN_NAMESPACE namespace fmt { FMT_INLINE_NAMESPACE v5 {
 
 #if !defined(FMT_HEADER_ONLY) && defined(_WIN32)
 # ifdef FMT_EXPORT