Addressing OE linking issues when built with GCC (#167)

* Use C++17 inline statics

This leads to better codegen in GCC, and fixes some linking issues in OE.

* Detect GCC and OE combination and fall-back to lock based ABA.

* clangformat

src/ds/defines.h

@@ -19,6 +19,10 @@
 #endif
 
 #if !defined(__clang__) && defined(__GNUC__)
+#  define GCC_NOT_CLANG
+#endif
+
+#ifdef GCC_NOT_CLANG
 #  if __GNUC__ >= 8
 #    define GCC_VERSION_EIGHT_PLUS
 #  endif