This file is included several times in a row, once for each element

$(cpp-src) of $(cpp-srcs-left). It sets libof-$(cpp-src) to $(lib)

for each.

cpp-src := $(firstword $(cpp-srcs-left)) cpp-srcs-left := $(filter-out $(cpp-src),$(cpp-srcs-left))

libof-$(notdir $(cpp-src)) := $(lib)