use -L${toolexeclibdir} instead of -L${libdir}
to be consistent with Makefile.am
prefix=@prefix@
exec_prefix=@exec_prefix@
libdir=@libdir@
+toolexeclibdir=@toolexeclibdir@
includedir=${libdir}/@PACKAGE_NAME@-@PACKAGE_VERSION@/include
Name: @PACKAGE_NAME@
Description: Library supporting Foreign Function Interfaces
Version: @PACKAGE_VERSION@
-Libs: -L${libdir} -lffi
+Libs: -L${toolexeclibdir} -lffi
Cflags: -I${includedir}