diff --git a/project/config/cfgdefs.sh b/project/config/cfgdefs.sh
index ce83da4..c04c86d 100644
--- a/project/config/cfgdefs.sh
+++ b/project/config/cfgdefs.sh
@@ -146,8 +146,8 @@ cfgdefs_output_custom_defs()
 cfgdefs_perform_common_tests()
 {
 	# headers
-	cfgtest_header_absence  'crypt.h'
 	cfgtest_header_absence  'stropts.h'
+	cfgtest_header_presence 'crypt.h'
 	cfgtest_header_presence 'stdatomic.h'
 	cfgtest_header_presence 'endian.h'
 	cfgtest_header_presence 'net/if.h'
@@ -162,6 +162,9 @@ cfgdefs_perform_common_tests()
 	cfgtest_header_presence 'sys/xattr.h'
 
 	# interfaces
+	mb_cfgtest_headers='crypt.h'
+	cfgtest_interface_presence 'crypt_r'
+
 	mb_cfgtest_headers='sys/epoll.h'
 	cfgtest_interface_presence 'epoll_create1'