wrapper: don't assume linux === glibc (updates #55)

Author: bpowers

src/gnu_wrapper.cc

@@ -13,11 +13,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/cdefs.h>
 #include <new>
 
-#include "heaplayers.h"
-
 /*
   To use this library,
   you only need to define the following allocation functions:
@@ -72,4 +69,7 @@ WEAK_REDEF1(size_t, malloc_usable_size, void *);
 }
 
 #include "wrapper.cc"
+#ifdef __GLIBC__
+// don't do this under musl
 #include "wrappers/gnuwrapper-hooks.cpp"
+#endif

src/wrapper.cc

@@ -217,7 +217,7 @@ extern "C" MESH_EXPORT int CUSTOM_MALLOC_SET_STATE(void * /* ptr */) {
   return 0;  // success.
 }
 
-#if defined(__GNUC__) && !defined(__FreeBSD__)
+#if defined(__GNUC__) && !defined(__FreeBSD__) && defined(__GLIBC__)
 extern "C" MESH_EXPORT struct mallinfo CUSTOM_MALLINFO() {
   // For now, we return useless stats.
   struct mallinfo m;