Transmission

This is what I have in .bashrc to compile transmission (I use only custom built curl in /usr/local/lib):
export CFLAGS="-O2 -march=core2 -pipe -fstack-protector"
export CXXFLAGS=$CFLAGS
export PKG_CONFIG_PATH="/usr/lib/pkgconfig:/usr/local/lib/pkgconfig"

Also you will have to have newer intltool ...

So you wish to keep the old one?

Then you have these options:

1. "Alternatively, you may set the environment variables LIBCURL_CFLAGS
and LIBCURL_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.", ie:
export LIBCURL_LIBS="-L/usr/local/lib/ -lcurl"
export ...

Looks like you have two verions of curl installed in /usr from yum and /usr/local from source/
You should not use in-system curl as it's simply too old, just uninstall it with "yum erase curl"
DL latest sources from upstream, make and install it. There are two ways to do it:
1) ./configure --prefix ...

Mine transmission-remote works fine with clear-text password, ie "-n user:password"

For all of us not using GTK frontend.

Here is a small app derived from transmission src:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/bn.h>
#include <openssl/des.h>
#include <openssl/dh.h>
#include <openssl/rand.h>
#include <assert.h>
#include <inttypes.h>

int tr ...