directory @var{prefix} one should set the @var{PKG_CONFIG_PATH}
environment variable to @var{prefix}/lib/pkgconfig for this to work.}
@example
-g++ -o simple `pkg-config --cflags --libs ginac` simple.cpp
+g++ -o simple simple.cpp `pkg-config --cflags --libs ginac`
@end example
This command line might expand to (for example):
@example
-g++ -o simple -lginac -lcln simple.cpp
+g++ -o simple simple.cpp -lginac -lcln
@end example
Not only is the form using @command{pkg-config} easier to type, it will