Adding “–no-binary pycparser” as recommended in the pycparser git issue tracker worked for me on a Raspberry Pi with Raspbian Jessie:
Change certbot-auto as follows:
diff --git a/certbot-auto b/certbot-auto
index 80f39cf..aba3a28 100755
--- a/certbot-auto
+++ b/certbot-auto
@@ -575,7 +575,8 @@ argparse==1.4.0 \
# This comes before cffi because cffi will otherwise install an unchecked
# version via setup_requires.
pycparser==2.14 \
- --hash=sha256:7959b4a74abdc27b312fed1c21e6caf9309ce0b29ea86b591fd2e99ecdf27f73
+ --hash=sha256:7959b4a74abdc27b312fed1c21e6caf9309ce0b29ea86b591fd2e99ecdf27f73 \
+ --no-binary pycparser
cffi==1.4.2 \
--hash=sha256:53c1c9ddb30431513eb7f3cdef0a3e06b0f1252188aaa7744af0f5a4cd45dbaf \