Note the rename in the ChangeLog, and update the instructions in the README file.

ChangeLog

@@ -1,3 +1,13 @@
+
+NEXT.VERSION
+
+  * IMPORTANT: the name of the library has changed to libjson-c.so and
+     the header files are now in include/json-c.
+     The pkgconfig name has also changed from json to json-c.
+     You should change your build to use appropriate -I and -l options.
+     A compatibility shim is in place so builds using the old name will
+     continue to work, but that will be removed in the next release.
+
 0.10
 
   * Add a json_object_to_json_string_ext() function to allow output to be

README

@@ -3,6 +3,8 @@ Building on Unix with git, gcc and autotools
 Home page for json-c:
   http://oss.metaparadigm.com/json-c/
 
+  Caution: do NOT use sources from svn.metaparadigm.com, they are old.
+
 Github repo for json-c:
   https://github.com/json-c/json-c
 
@@ -20,9 +22,15 @@ To build and run the test programs run
 
     $ make check
 
-Linking to libjson
+Linking to libjson-c
 
 If your system has pkgconfig then you can just add this to your makefile
 
-CFLAGS += $(shell pkg-config --cflags json)
-LDFLAGS += $(shell pkg-config --libs json)
+CFLAGS += $(shell pkg-config --cflags json-c)
+LDFLAGS += $(shell pkg-config --libs json-c)
+
+Without pkgconfig, you would do something like this:
+
+JSON_C_DIR=/path/to/json_c/install
+CFLAGS += -I$(JSON_C_DIR)/include/json-c
+LDFLAGS+= -L$(JSON_C_DIR)/lib -ljson-c