Fix build against json-c-0.14 (#609)
Fix build against json-c-0.14 (#609)

The new pkgconfig file contains two include directories:

  Cflags: -I${includedir} -I${includedir}/json-c

Apparently pkg_check_modules returns them as a semicolon-separated
string ("CMake list"), which causes the build to fail when appended
directly to CMAKE_C_FLAGS.
zmap/zmap,zmap/zmap,zmap/zmap