How to fix library search errors in cmake?

Question

CMake

I'm trying to figure out with cmake to automate the assembly of cross-platform applications. I got to the point of using third-party libraries and ran into the following problem.
Example on github . Curl code was taken as an example, which compiles and works fine.
Compiled CMakeLists.txt for this project. And I tried to compile, I build for tests in 2 systems FreeBSD 10 and Fedora 21. And I came across a problem with finding libraries. I broke my head in 3 days of searching, but I did not solve the problem.
Trying to build on Fedora throws a library search error.

CMake Error at /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:136 (message):
  Could NOT find LibXml2 (missing: LIBXML2_LIBRARIES LIBXML2_INCLUDE_DIR)
Call Stack (most recent call first):
  /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:343 (_FPHSA_FAILURE_MESSAGE)
  /usr/share/cmake/Modules/FindLibXml2.cmake:69 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  CMakeLists.txt:9 (find_package)

At the same time, the FindLibXml2.cmake search plugin is in its proper place. But he doesn't find it.
Under FreeBSD 10, the same operation fails and produces a Makefile that does not work. While searching for problems, I found that the library search in the LIBXML2_INCLUDE_DIRS variable instead of the correct path ( /usr/local/include/libxml2/ ) writes the following /usr/local/include/usr/include/usr/include
And when trying to build the resulting Makefile, we get an error about inability to find header files in the specified directories. If you manually rewrite the LIBXML2_INCLUDE_DIRS value, then the generated Makefile builds the program perfectly.
After such a long and, I beg your pardon, chaotic explanation, two questions.
1. Who is to blame? (As I understand it, the search modules of the LibXml2 library for cmake are incorrect?)
2. What should I do? (how to ensure a "problem-free" assembly on different systems, because such glitches can appear on different OS and with different libraries? I can't check everything, and I just want to use cmake for this reason)?