diff --git a/Lib/distutils/sysconfig.py b/Lib/distutils/sysconfig.py
index 9993fba..5cf9d1f 100644
--- a/Lib/distutils/sysconfig.py
+++ b/Lib/distutils/sysconfig.py
@@ -165,6 +165,7 @@ def customize_compiler(compiler):
         (cc, cxx, opt, cflags, ccshared, ldshared, so_ext) = \
             get_config_vars('CC', 'CXX', 'OPT', 'CFLAGS',
                             'CCSHARED', 'LDSHARED', 'SO')
+        cflags += get_config_var('CPPFLAGS')
 
         if 'CC' in os.environ:
             cc = os.environ['CC']