diff --git a/configure.ac b/configure.ac
index 5b6252390..4facd17c8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -105,7 +105,7 @@ AC_LANG([C])
 
 AC_C_CONST
 
-AC_CHECK_FUNCS(strndup strtok_r sigaction)
+AC_CHECK_FUNCS(strndup strtok_r sigaction malloc_trim)
 AC_CHECK_FUNCS(aligned_alloc posix_memalign _aligned_malloc)
 
 AC_FUNC_ALLOCA
diff --git a/link-grammar/parse/extract-links.c b/link-grammar/parse/extract-links.c
index ec0b2324f..91bac5988 100644
--- a/link-grammar/parse/extract-links.c
+++ b/link-grammar/parse/extract-links.c
@@ -282,7 +282,7 @@ void free_extractor(extractor_t * pex)
 	pex->x_table_size = 0;
 	pex->x_table = NULL;
 
-#if defined __GLIBC__
+#if HAVE_MALLOC_TRIM
 	// MST parsing can result in pathological cases, with almost a
 	// billion elts in the Parse_choice_pool. This blows up the
 	// resident-set size (RSS) over time. Avoid this issue by trimming.
@@ -298,7 +298,7 @@ void free_extractor(extractor_t * pex)
 
 	xfree((void *) pex, sizeof(extractor_t));
 
-#if defined __GLIBC__
+#if HAVE_MALLOC_TRIM
 	// malloc_trim() is a gnu extension.  An alternative would be
 	// to call madvise(MADV_DONTNEED) but this is more complicated.
 	if (trim) malloc_trim(0);
diff --git a/link-grammar/resources.c b/link-grammar/resources.c
index 18fa2bf91..19da17771 100644
--- a/link-grammar/resources.c
+++ b/link-grammar/resources.c
@@ -48,7 +48,7 @@ int getrusage(int who, struct rusage *rusage);
 /** Returns the CPU usage time, for this thread only, in seconds. */
 static double current_usage_time(void)
 {
-#if !defined(_WIN32) && !defined(__APPLE__)
+#if defined RUSAGE_THREAD
 	struct rusage u;
 	getrusage (RUSAGE_THREAD, &u);
 	return (u.ru_utime.tv_sec + ((double) u.ru_utime.tv_usec) / 1000000.0);