diff --git a/tests/Makefile.am b/tests/Makefile.am
index f0deb600..6f25b3f0 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -116,19 +116,19 @@ check_PROGRAMS = \
 
 clock_xettime_LDADD = -lrt
 filter_unavailable_LDADD = -lpthread
-fstat64_CFLAGS = $(AM_CFLAGS) -D_FILE_OFFSET_BITS=64
-fstatat64_CFLAGS = $(AM_CFLAGS) -D_FILE_OFFSET_BITS=64
-ftruncate64_CFLAGS = $(AM_CFLAGS) -D_FILE_OFFSET_BITS=64
-lstat64_CFLAGS = $(AM_CFLAGS) -D_FILE_OFFSET_BITS=64
-mmap64_CFLAGS = $(AM_CFLAGS) -D_FILE_OFFSET_BITS=64
+fstat64_CPPFLAGS = $(AM_CPPFLAGS) -D_FILE_OFFSET_BITS=64
+fstatat64_CPPFLAGS = $(AM_CPPFLAGS) -D_FILE_OFFSET_BITS=64
+ftruncate64_CPPFLAGS = $(AM_CPPFLAGS) -D_FILE_OFFSET_BITS=64
+lstat64_CPPFLAGS = $(AM_CPPFLAGS) -D_FILE_OFFSET_BITS=64
+mmap64_CPPFLAGS = $(AM_CPPFLAGS) -D_FILE_OFFSET_BITS=64
 mq_LDADD = -lrt
-newfstatat_CFLAGS = $(AM_CFLAGS) -D_FILE_OFFSET_BITS=64
+newfstatat_CPPFLAGS = $(AM_CPPFLAGS) -D_FILE_OFFSET_BITS=64
 pc_LDADD = $(dl_LIBS)
-stat64_CFLAGS = $(AM_CFLAGS) -D_FILE_OFFSET_BITS=64
-statfs_CFLAGS = $(AM_CFLAGS) -D_FILE_OFFSET_BITS=64
+stat64_CPPFLAGS = $(AM_CPPFLAGS) -D_FILE_OFFSET_BITS=64
+statfs_CPPFLAGS = $(AM_CPPFLAGS) -D_FILE_OFFSET_BITS=64
 times_LDADD = -lrt
-truncate64_CFLAGS = $(AM_CFLAGS) -D_FILE_OFFSET_BITS=64
-uio_CFLAGS = $(AM_CFLAGS) -D_FILE_OFFSET_BITS=64
+truncate64_CPPFLAGS = $(AM_CPPFLAGS) -D_FILE_OFFSET_BITS=64
+uio_CPPFLAGS = $(AM_CPPFLAGS) -D_FILE_OFFSET_BITS=64
 stack_fcall_SOURCES = stack-fcall.c \
 	stack-fcall-0.c stack-fcall-1.c stack-fcall-2.c stack-fcall-3.c