Check for openssl dependency in configure

[lhunath]

OpenSSL is required for the build of scrypt, configure should check for its availability to avoid build errors such as:

libcperciva/crypto/crypto_aes.c:6:10: fatal error: 'openssl/aes.h' file not found
#include <openssl/aes.h>

[cperciva]

That's what this bit in configure.ac is for:

AC_SEARCH_LIBS([AES_encrypt], [crypto],,
    AC_MSG_ERROR([function AES_ENCRYPT not found]))

Do you have OpenSSL installed but not its headers?

[lhunath]

Correct, OS X El Capitan ships with the OpenSSL binaries but not the headers, presumably in an attempt to enforce their deprecation of OpenSSL.

[cperciva]

Ick. Ok, I'll add some code to handle that.

[lhunath]

As an aside, I've opted to do this before running configure, to ensure scrypt builds with homebrew's openssl if installed:

if hash brew 2>/dev/null; then
    opensslPath=$(brew --prefix openssl)
    export CFLAGS="$CFLAGS -I$opensslPath/include"
    export LDFLAGS="$LDFLAGS -L$opensslPath/lib"
fi

[aaron-baby]

@lhunath thanks for sharing

[bigendiansmalls]

@gperciva I think this could be closed now, no?

[gperciva]

Yes, thanks!