Another one that might be due to inter-translation unit analysis weaknesses. An
assert() will clear it. See http://clang-analyzer.llvm.org/faq.html.

libtool: link: /usr/local/bin/scan-build/ccc-analyzer -I/usr/local/include -g3
-O1 -fvisibility=hidden -Wall -o dsa-rfc6979 dsa-rfc6979.o
../src/.libs/libgcrypt.a -L/usr/local/lib ../compat/.libs/libcompat.a
/usr/local/lib/libgpg-error.so
/usr/local/bin/scan-build/ccc-analyzer -DHAVE_CONFIG_H -I. -I.. -I../src
-I../src -I/usr/local/include -g3 -O1 -fvisibility=hidden -Wall -MT t-ed25519.o
-MD -MP -MF .deps/t-ed25519.Tpo -c -o t-ed25519.o t-ed25519.c
t-ed25519.c:182:10: warning: Dereference of null pointer (loaded from variable 'p')

*p = 0;
 ~ ^

1 warning generated.