[libgd] meson: Update readme

[Patrick Griffis <pgriffis src gnome org>]

commit 44f7d2673d4ba19be99dfe6a775b18e67bc4b56e
Author: Patrick Griffis <tingping tingping se>
Date:   Tue Feb 21 00:10:50 2017 -0500

    meson: Update readme
    
    Include more info about using as a shared library.

 meson_readme.md |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/meson_readme.md b/meson_readme.md
index 092cba8..c3e7f26 100644
--- a/meson_readme.md
+++ b/meson_readme.md
@@ -3,7 +3,10 @@ See README for general information. Read below for usage with Meson.
 Usage
 =====
 
-libgd is intended to be used as a submodule from other projects. This requires passing default_options to 
the subproject which was added in Meson 0.38.0. To see a full list of options you can run `mesonconf 
$your_build_dir`. If building a non-static library `pkglibdir` must be set to a private location to install 
to. For introspection files you also must set `pkgdatadir`.
+libgd is intended to be used as a submodule from other projects. This requires passing default_options to 
the subproject
+which was added in Meson 0.38.0. To see a full list of options you can run `mesonconf $your_build_dir`. If 
building a
+non-static library `pkglibdir` must be set to a private location to install to which you will also want to 
pass (an absolute path)
+with the `install_rpath` keyword to any executables. For introspection files you also must set `pkgdatadir`.
 
 So given a Meson project using git you would run this to do initial setup: