On a clean 16.04 server machine I will build apache. Desktop instructions should be no different.
>more /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04 LTS"
Install wllvm
>sudo apt-get update
>sudo install python-pip
>sudo pip install wllvm
I am only going to build apache, not apr, so I first install the prerequisites.
>sudo apt-get install llvm clang libapr1-dev libaprutil1-dev libpcre3-dev make
At this point, you could check your clang version with which clang and ls -l /usr/bin/clang.
It should be at least clang-3.8.
Configure the wllvm tool to use clang and be relatively quiet:
>export LLVM_COMPILER=clang
>export WLLVM_OUTPUT=WARNING
Fetch apache, untar, configure, then build:
>wget https://archive.apache.org/dist/httpd/httpd-2.4.23.tar.gz
>tar xfz httpd-2.4.23.tar.gz
>cd httpd-2.4.23
>CC=wllvm ./configure
>make
Extract the bitcode.
>extract-bc httpd
>ls -la httpd.bc
-rw-r--r-- 1 vagrant vagrant 1119584 Aug 4 20:02 httpd.bc
Turn the bitcode into a second executable binary. (optional -- just for fun and sanity checking)
llc -filetype=obj httpd.bc
gcc httpd.o -lpthread -lapr-1 -laprutil-1 -lpcre -o httpd.new