$HOME/src is where I put the code in this example. You can pick wherever you like.
$ cd $HOME/src
$ git clone https://boringssl.googlesource.com/boringssl
$ cd boringssl
$ mkdir build
$ cd build
$ cmake -DCMAKE_POSITION_INDEPENDENT_CODE=on ..
In the boringssl source tree root, make sure there is a
libdir should contain the two libs (I made them symlinks into the build dir). The
includedir is already present by default. Make and populate
liblike this (commands issued in the source tree root, not in the
$ mkdir lib
$ cd lib
$ ln -s ../build/ssl/libssl.a
$ ln -s ../build/crypto/libcrypto.a
LIBS=-lpthread ./configure --with-ssl=$HOME/src/boringssl(where I point out the root of the boringssl tree)
Verify that at the end of the configuration, it says it detected BoringSSL to be used.
makein the curl source tree.
Now you can install curl normally with