pkgconfig file incorrectly exposes internal dependencies

[AdamWill]

Both Fedora and Debian have reports indicating that pion's pkgconfig file has issues:

https://bugzilla.redhat.com/show_bug.cgi?id=754975#c3
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=678508

(Debian's got closed as the package was renamed, but the report still appears to be essentially valid). I am not exactly an expert, but as I understand it the Libs: line shouldn't list all the flags needed to compile pion itself, but only the flags needed to build against pion, which should be just -L${libdir} -lpion. pion's idea of appropriate Cflags for compiling pion itself also probably shouldn't be in the pkgconfig file.

A patch for this was added to Fedora during package review. Re-diffing it for pion 5.0.7, I get this:

--- pion-2b16caeedc9b0ffd275867b157305c333c0f118d/pion.pc.in    2014-10-17 12:42:29.000000000 -0700
+++ pion-2b16caeedc9b0ffd275867b157305c333c0f118d/pion.pc.in.new    2015-07-28 13:41:20.923907530 -0700
@@ -11,5 +11,6 @@
 Description: a C++ framework for building lightweight HTTP interfaces
 Version: @VERSION@
 #Requires: boost-1.35
-Libs: @LDFLAGS@ @PION_EXTERNAL_LIBS@ -L${libdir} -lpion
-Cflags: @CPPFLAGS@ -I${includedir}
+Libs: -L${libdir} -lpion
+Libs.private: @PION_EXTERNAL_LIBS@
+Cflags: -I${includedir}