diff --git a/lib/libc/tests/stdlib/Makefile b/lib/libc/tests/stdlib/Makefile
index 4a08f8557d08..23e899608fd4 100644
--- a/lib/libc/tests/stdlib/Makefile
+++ b/lib/libc/tests/stdlib/Makefile
@@ -14,6 +14,9 @@ ATF_TESTS_CXX+=		cxa_thread_atexit_test
 ATF_TESTS_CXX+=		cxa_thread_atexit_nothr_test
 .endif
 
+# All architectures on FreeBSD have fenv.h
+CFLAGS+=	-D__HAVE_FENV
+
 # Not sure why this isn't defined for all architectures, since most
 # have long double.
 .if ${MACHINE_CPUARCH} == "aarch64" || \
diff --git a/lib/msun/tests/Makefile b/lib/msun/tests/Makefile
index 949b0a5b7aad..6c8cee976173 100644
--- a/lib/msun/tests/Makefile
+++ b/lib/msun/tests/Makefile
@@ -99,6 +99,8 @@ ARCH_SUBDIR= ${MACHINE_CPUARCH}
 # precision is.
 CFLAGS+=	-DLDBL_PREC=${LDBL_PREC}
 
+CFLAGS.fe_round_test+=	-D__HAVE_FENV
+
 .include <netbsd-tests.test.mk>
 
 .include <bsd.test.mk>