diff --git a/lib/hostares.c b/lib/hostares.c
index 13c0dc237..af02d8dc8 100644
--- a/lib/hostares.c
+++ b/lib/hostares.c
@@ -26,8 +26,6 @@
 #include <string.h>
 #include <errno.h>
 
-#define _REENTRANT
-
 #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
 #include <malloc.h>
 #else
diff --git a/lib/hostasyn.c b/lib/hostasyn.c
index e37db2755..d1b7cdd18 100644
--- a/lib/hostasyn.c
+++ b/lib/hostasyn.c
@@ -26,8 +26,6 @@
 #include <string.h>
 #include <errno.h>
 
-#define _REENTRANT
-
 #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
 #include <malloc.h>
 #else
diff --git a/lib/hostip.c b/lib/hostip.c
index 233d81cf3..91f59af2a 100644
--- a/lib/hostip.c
+++ b/lib/hostip.c
@@ -26,8 +26,6 @@
 #include <string.h>
 #include <errno.h>
 
-#define _REENTRANT
-
 #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
 #include <malloc.h>
 #else
diff --git a/lib/hostip4.c b/lib/hostip4.c
index 178f3b9da..cebc74d58 100644
--- a/lib/hostip4.c
+++ b/lib/hostip4.c
@@ -26,8 +26,6 @@
 #include <string.h>
 #include <errno.h>
 
-#define _REENTRANT
-
 #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
 #include <malloc.h>
 #else
diff --git a/lib/hostip6.c b/lib/hostip6.c
index 0c5eaa03c..b273efe00 100644
--- a/lib/hostip6.c
+++ b/lib/hostip6.c
@@ -26,8 +26,6 @@
 #include <string.h>
 #include <errno.h>
 
-#define _REENTRANT
-
 #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
 #include <malloc.h>
 #else
diff --git a/lib/hostsyn.c b/lib/hostsyn.c
index 38030b7f0..a385632e9 100644
--- a/lib/hostsyn.c
+++ b/lib/hostsyn.c
@@ -26,8 +26,6 @@
 #include <string.h>
 #include <errno.h>
 
-#define _REENTRANT
-
 #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
 #include <malloc.h>
 #else
diff --git a/lib/hostthre.c b/lib/hostthre.c
index b05729404..dd3f896c9 100644
--- a/lib/hostthre.c
+++ b/lib/hostthre.c
@@ -26,8 +26,6 @@
 #include <string.h>
 #include <errno.h>
 
-#define _REENTRANT
-
 #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
 #include <malloc.h>
 #else
diff --git a/lib/setup.h b/lib/setup.h
index a248e0669..b44e777c9 100644
--- a/lib/setup.h
+++ b/lib/setup.h
@@ -95,13 +95,13 @@ typedef unsigned char bool;
 #define FORMAT_OFF_T "ld"
 #endif
 
-/*#ifdef NEED_REENTRANT*/
+#ifndef _REENTRANT
 /* Solaris needs _REENTRANT set for a few function prototypes and things to
    appear in the #include files. We need to #define it before all #include
    files. Unixware needs it to build proper reentrant code. Others may also
    need it. */
 #define _REENTRANT
-/*#endif */
+#endif
 
 #include <stdio.h>
 #ifdef HAVE_ASSERT_H