diff --git a/src/lib/libast/comp/getopt.c b/src/lib/libast/comp/getopt.c
index 586947217..01a05202e 100644
--- a/src/lib/libast/comp/getopt.c
+++ b/src/lib/libast/comp/getopt.c
@@ -43,8 +43,12 @@ char*		optarg = 0;
 
 static int	lastoptind;
 
+/*
+ * Avoid a null-test optimization bug caused by glibc's headers
+ * by naming this function '_ast_getopt' instead of 'getopt'.
+ */
 extern int
-getopt(int argc, char* const* argv, const char* optstring)
+_ast_getopt(int argc, char* const* argv, const char* optstring)
 {
 	int	n;
 
diff --git a/src/lib/libast/features/map.c b/src/lib/libast/features/map.c
index 3d9e74c63..660d4d5cb 100644
--- a/src/lib/libast/features/map.c
+++ b/src/lib/libast/features/map.c
@@ -113,9 +113,12 @@ main()
 #endif
 	printf("#undef	getdate\n");
 	printf("#define getdate		_ast_getdate\n");
-#if _lib_getopt || _lib_getsubopt || _lib_getopt_long || _lib_getopt_long_only
+#endif
+	/* libast always provides its own getopt implementation */
 	printf("#undef	getopt\n");
 	printf("#define getopt		_ast_getopt\n");
+#if _map_libc
+#if _lib_getopt || _lib_getsubopt || _lib_getopt_long || _lib_getopt_long_only
 	printf("#undef	getsubopt\n");
 	printf("#define getsubopt       _ast_getsubopt\n");
 	printf("#undef	getopt_long\n");
@@ -447,9 +450,6 @@ main()
 	printf("#undef	realloc\n");
 	printf("#define realloc		_ast_realloc\n");
 	printf("extern void*		realloc(void*, size_t);\n");
-	printf("#undef	strdup\n");
-	printf("#define strdup		_ast_strdup\n");
-	printf("extern char*		strdup(const char*);\n");
 #if _lib_valloc
 	printf("#undef	valloc\n");
 	printf("#define valloc		_ast_valloc\n");
@@ -457,6 +457,10 @@ main()
 #endif
 #endif
 #endif
+	/* we always use the libast strdup implementation */
+	printf("#undef	strdup\n");
+	printf("#define strdup		_ast_strdup\n");
+	printf("extern char*		strdup(const char*);\n");
 
 	/*
 	 * overriding <stdlib.h> strto*() is problematic to say the least
diff --git a/src/lib/libast/string/strdup.c b/src/lib/libast/string/strdup.c
index e2a8be5b6..7a17b45d2 100644
--- a/src/lib/libast/string/strdup.c
+++ b/src/lib/libast/string/strdup.c
@@ -51,19 +51,15 @@ __STDPP__directive pragma pp:nohide strdup
 #endif
 
 /*
- * Work around a null-test optimization bug in GCC.
+ * Avoid a null-test optimization bug caused by glibc's headers
+ * by naming this function '_ast_strdup' instead of 'strdup'.
  * https://bugzilla.redhat.com/1221766
  */
-#pragma GCC push_options
-#pragma GCC optimize ("O0")
-
 extern char*
-strdup(register const char* s)
+_ast_strdup(const char* s)
 {
 	register char*	t;
 	register int	n;
 
 	return (s && (t = oldof(0, char, n = strlen(s) + 1, 0))) ? (char*)memcpy(t, s, n) : (char*)0;
 }
-
-#pragma GCC pop_options