diff --git a/configure.ac b/configure.ac
index c1c33e6..22992fc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -191,6 +191,7 @@
 AC_CHECK_TYPES([struct mallinfo],,, [#include <malloc.h>])
 AC_CHECK_TYPES([Elf32_Versym],,, [#include <elf.h>])   # for vdso_support.h
 AC_CHECK_FUNCS(sbrk)            # for tcmalloc to get memory
+AC_CHECK_FUNCS(__sbrk)          # for tcmalloc to get memory
 AC_CHECK_FUNCS(geteuid)         # for turning off services when run as root
 AC_CHECK_FUNCS(fork)            # for the pthread_atfork setup
 AC_CHECK_HEADERS(features.h)    # for vdso_support.h
diff --git a/src/malloc_hook_mmap_linux.h b/src/malloc_hook_mmap_linux.h
index 0d0c2a8..0eec895 100644
--- a/src/malloc_hook_mmap_linux.h
+++ b/src/malloc_hook_mmap_linux.h
@@ -207,7 +207,7 @@
   return result;
 }
 
-#ifndef __UCLIBC__
+#ifdef HAVE___SBRK
 // libc's version:
 extern "C" void* __sbrk(intptr_t increment);