SSL not available when attempting to compile “wget” from source?

Question

I was trying to install wget from source in Linux by:

./configure --with-ssl=openssl

But it returns me:

configure: error: --with-ssl=openssl was given, but SSL is not available.

If I do:

root@qemux86:/mnt/sdc2/wget-1.16# which openssl
/mnt/sdc2/miniconda/bin/openssl

So OpenSSL must have been installed. Why it still says SSL is not available?

Answer 1

So OpenSSL must be installed. Why it still says SSL is not available?

Yes, OpenSSL is installed as an already compiled binary on your system, but the shared libraries and related headers needed for source compilation are not installed. Thus that configure error when you attempt to compile wget from source; you need to install those shared libraries to compile successfully with the --with-ssl=openssl flag.

To check if the OpenSSL libraries are installed on your system, just run ldconfig like this:

ldconfig -p | grep ssl

And the output should be something like this; taken from a running Ubuntu system I manage:

libssl.so.1.0.0 (libc6,x86-64) => /lib/x86_64-linux-gnu/libssl.so.1.0.0
libssl.so (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/libssl.so

If your output is blank, shared libraries for OpenSSL are not installed. So you should install them.

Unsure what flavor of Linux you are using, but un Ubuntu/Debian you would run this via apt-get command to get that installed:

sudo apt-get install libssl-dev

And on a CentOS/RedHat system you would install it via yum like this:

yum install -y openssl-devel

Also if you are somehow worried about installing shared libraries on your system, don’t worry. They basically just sit there and do nothing until needed for compilation or runtime usage by a program. Meaning the files would only take up physical space on the system and would not add an extra CPU or memory load on your system by simply being installed.