docs: Add example of setting PKG_CONFIG_PATH on OSX with macports

Change-Id: Iaf922519fcce8569f514d7994fa0db9766e0cc88
Refs: #1453
diff --git a/INSTALL.md b/INSTALL.md
index 8abbcc8..cf8bfcc 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -18,7 +18,7 @@
 
 * `libpcap`
 
-    Comes with base on Mac OS X 10.8 and 10.9:
+    Comes with base on OS X 10.8 and 10.9:
 
     On Ubuntu >= 12.04:
 
@@ -30,7 +30,7 @@
 * `graphviz`
 * `python-sphinx`
 
-    On Mac OS X 10.8 and 10.9 with macports:
+    On OS X 10.8 and 10.9 with macports:
 
         sudo port install doxygen graphviz py27-sphinx sphinx_select
         sudo port select sphinx py27-sphinx
@@ -40,7 +40,6 @@
         sudo apt-get install doxygen graphviz python-sphinx
 
 
-
 ## Build
 
 The following commands should be used to build NFD:
@@ -49,11 +48,21 @@
     ./waf
     sudo ./waf install
 
-Refer to `README.md` file for more options that can be used during `configure` stage and how to properly configure and run NFD.
+Refer to `README.md` file for more options that can be used during `configure` stage and
+how to properly configure and run NFD.
 
-In some configurations, configuration step may require small modification:
+In some configurations, configuration step may require small modification.  For example,
+on OSX that uses macports (correct the path if macports was not installed in the default
+path `/opt/local`):
 
-    export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:/usr/lib/pkgconfig:/usr/lib64/pkgconfig
+    export PKG_CONFIG_PATH=/opt/local/lib/pkgconfig:/usr/local/lib/pkgconfig:/usr/lib/pkgconfig:$PKG_CONFIG_PATH
+    ./waf configure
+    ./waf
+    sudo ./waf install
+
+On some Linux distributions (e.g., Fedora 20):
+
+    export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:/usr/lib/pkgconfig:/usr/lib64/pkgconfig:$PKG_CONFIG_PATH
     ./waf configure
     ./waf
     sudo ./waf install
@@ -64,7 +73,14 @@
 
     ./waf doxygen
 
-Note that manpages are automatically created and installed during the normal build process (e.g., during `./waf` and `./waf install`), if `python-sphinx` module is detected during `./waf configure` stage.
-By default, manpages are installed into `${PREFIX}/share/man` (where default value for `PREFIX` is `/usr/local`).
-This location can be changed during `./waf configure` stage using `--prefix`, `--datarootdir`, or `--mandir` options.
+Note that manpages are automatically created and installed during the normal build process
+(e.g., during `./waf` and `./waf install`), if `python-sphinx` module is detected during
+`./waf configure` stage.  By default, manpages are installed into `${PREFIX}/share/man`
+(where default value for `PREFIX` is `/usr/local`).  This location can be changed during
+`./waf configure` stage using `--prefix`, `--datarootdir`, or `--mandir` options.
+
 For more details, refer to `./waf --help`.
+
+Additional documentation in `build/docs` can be built using (requires `python-sphinx` package)
+
+    ./waf sphinx
diff --git a/README.md b/README.md
index de446f2..04aadb5 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,10 @@
 You may override `SYSCONFDIR` and `PREFIX` by specifying their
 corresponding options during installation:
 
-    ./waf install --prefix <path/for/prefix> --sysconfdir <some/other/path>
+    ./waf configure --prefix <path/for/prefix> --sysconfdir <some/other/path>
+
+Refer to `INSTALL.md` for more detailed instructions on how to compile
+and install NFD.
 
 ## Running and Configuring NFD