json-c12 and 13 has invalid spec with Cflags: -I${includedir}/json-c

[ni4]

Having installed json-c12-devel from this repository on rhel8/ubi container, got the issues linking to the json-c12 with the CMake message:

CMake Error in src/tests/CMakeLists.txt:
  Imported target "JSON-C::JSON-C" includes non-existent path

    "/usr/include/json-c"

  in its INTERFACE_INCLUDE_DIRECTORIES.

After the check it appears that installed /usr/lib64/pkgconfig/json-c12.pc has the following contents, which should be a cause of error (notice Cflags has json-c, without the 12):

[root@ceca4766267b opt]# cat /usr/lib64/pkgconfig/json-c12.pc 
prefix=/usr
exec_prefix=/usr
libdir=/usr/lib64
includedir=/usr/include

Name: json-c
Description: JSON implementation in C
Version: 0.12.1
Requires: 
Libs:  -L${libdir} -ljson-c12
Cflags: -I${includedir}/json-c