diff --git a/utils/tomcrypt/Makefile b/utils/tomcrypt/Makefile
index 3382819a66..f0d874c1ae 100644
--- a/utils/tomcrypt/Makefile
+++ b/utils/tomcrypt/Makefile
@@ -25,13 +25,18 @@ endif
 CFLAGS := -O3 -g -std=c99 -Wall $(DEFINES) -Isrc/headers
 LDFLAGS :=
 
+CPPDEFINES := $(shell echo foo | $(CROSS)$(CC) -dM -E -)
+ifeq ($(findstring __clang__,$(CPPDEFINES)),__clang__)
+CFLAGS += -mmacosx-version-min=10.5
 ifneq ($(ISYSROOT),)
 CFLAGS += -isysroot $(ISYSROOT)
 endif
+endif
 
 SOURCES := \
 	src/ciphers/aes/aes.c src/ciphers/aes/aes_tab.c \
-	src/misc/crypt/crypt_argchk.c src/misc/crypt/crypt_register_cipher.c src/misc/crypt/crypt_cipher_is_valid.c src/misc/crypt/crypt_cipher_descriptor.c \
+	src/misc/crypt/crypt_argchk.c src/misc/crypt/crypt_register_cipher.c \
+	src/misc/crypt/crypt_cipher_is_valid.c src/misc/crypt/crypt_cipher_descriptor.c \
 	src/misc/zeromem.c src/misc/compare_testvector.c \
 	src/modes/cbc/cbc_start.c src/modes/cbc/cbc_decrypt.c src/modes/cbc/cbc_encrypt.c \
 	src/hashes/sha1.c