Merge pull request #310 from pangenome/jemalloc_readme

more explicit README regarding the dependencies

README.md

@@ -20,14 +20,22 @@ The RAM and computational savings are substantial.  In partially ordered regions
 
 ### building from source
 
-`odgi`requires a C++ version of 9.3 or higher. You can check your version via:
+`odgi` requires a C++ version of 9.3 or higher. You can check your version via:
 
 ``` bash
 gcc --version
 g++ --version
 ```
 
-Clone the `odgi` git repository recursively because of the many submodules and build with:
+`odgi` pulls in a host of source repositories as dependencies. It may be necessary to install several system-level 
+libraries to build `odgi`. On `Ubuntu 20.04`, these can be installed using `apt`:
+
+```
+sudo apt install build-essential cmake python3-distutils python3-dev libjemalloc-dev
+```
+
+After installing the required dependencies, clone the `odgi` git repository recursively because of the many submodules
+and build with:
 
 ```
 git clone --recursive https://github.com/pangenome/odgi.git
@@ -44,10 +52,17 @@ cmake -DBUILD_STATIC=1 -H. -Bbuild && cmake --build build -- -j 3
 You'll need to set this flag to 0 or remove and rebuild your build directory if you want to unset this build behavior and get a dynamic binary again.
 Static builds are unlikely to be supported on OSX, and require appropriate static libraries on linux.
 
-`odgi` pulls in a host of source repositories as dependencies. It may be necessary to install several system-level libraries to build odgi.
- On Ubuntu 20.04, these can be installed using apt: `sudo apt install build-essential cmake python3-distutils python3-dev libjemalloc-dev`.
 
-Alternatively, after `sudo apt install guix`, start a GNU Guix build container with:
+#### Notes on dependencies
+
+On `Arch Linux`, the `jemalloc` dependency can be installed with:
+
+```
+sudo pacman -S jemalloc     # arch linux
+```
+
+An alternative way to manage `odgi`'s dependencies is to use `GUIX`. After `sudo apt install guix`, start a GNU Guix
+build container with:
 
 ```bash
 source ./.guix-build