diff --git a/src/common/autoconfig.h.in b/src/common/autoconfig.h.in
index c6dc665a..e46b702e 100644
--- a/src/common/autoconfig.h.in
+++ b/src/common/autoconfig.h.in
@@ -45,6 +45,9 @@
 /* Define to 1 if you have the `z' library (-lz). */
 #undef HAVE_LIBZ
 
+/* Define to 1 if you have the `malloc_trim' function. */
+#undef HAVE_MALLOC_TRIM
+
 /* Define to 1 if you have the <memory.h> header file. */
 #undef HAVE_MEMORY_H
 
diff --git a/src/configure.ac b/src/configure.ac
index 85c6ca73..e47eecae 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -37,7 +37,7 @@ AC_SYS_LARGEFILE
 # OpenBSD needs sys/param.h for mount.h to compile
 AC_CHECK_HEADERS([sys/param.h, spawn.h])
 
-AC_CHECK_FUNCS([posix_spawn setrlimit kqueue vsnprintf])
+AC_CHECK_FUNCS([posix_spawn setrlimit kqueue vsnprintf malloc_trim])
 
 if test "x$ac_cv_func_posix_spawn" = xyes; then :
    AC_ARG_ENABLE(posix_spawn,
diff --git a/src/internfile/mh_xslt.cpp b/src/internfile/mh_xslt.cpp
index 3b80fa2c..26a02782 100644
--- a/src/internfile/mh_xslt.cpp
+++ b/src/internfile/mh_xslt.cpp
@@ -52,9 +52,9 @@ public:
 			// malloc_trim() and mallopt() doc seems to be a bit
 			// misleading, there is probably a frag size under which
 			// free() does not try to malloc_trim() at all
-#ifndef _WIN32
+#ifdef HAVE_MALLOC_TRIM
 			malloc_trim(0);
-#endif
+#endif /* HAVE_MALLOC_TRIM */
         }
     }