Use Requires.private in *.pc files to not add unnecessary links.
diff --git a/src/libplist++.pc.in b/src/libplist++.pc.in
index cea869c..0fce9d1 100644
--- a/src/libplist++.pc.in
+++ b/src/libplist++.pc.in
@@ -8,4 +8,4 @@
 Version: @PACKAGE_VERSION@
 Libs: -L${libdir} -lplist++
 Cflags: -I${includedir}
-Requires: libplist >= @PACKAGE_VERSION@
+Requires.private: libplist >= @PACKAGE_VERSION@