build : fix build info generation and cleanup Makefile (#3920)

* cmake : fix joining of REAL_GIT_DIR

* fix includes with help from include-what-you-use

* make : remove unneeded deps and add test-rope target

* fix C includes in C++ source files

* Revert "fix includes with help from include-what-you-use"

This reverts commit 635e9fadfd516d4604a0fecf4a854bfb25ad17ae.