Add FindJSONC.cmake

modules/FindJSONC.cmake

+# Find json-c
+
+find_library(JSONC_LIBRARIES
+    NAMES json-c json
+    HINTS /lib /lib64 /usr/lib /usr/lib64 
+    DOC "json-c library"
+)
+
+find_path(JSONC_INCLUDE_DIRS
+     NAMES json.h
+    HINTS /usr/include/json /usr/include/json-c
+    DOC "json-c headers"
+)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(json-c
+    DEFAULT_MSG JSONC_LIBRARIES JSONC_INCLUDE_DIRS
+)
+mark_as_advanced(JSONC_INCLUDE_DIRS JSONC_LIBRARIES)