Bridge to CMake to handle pre-built automake libraries from 'common'

[Miha22]

There has to be note to create/generate: AUTHORS Changelog NEWS, config (for autoheader) and "m4" dir, and issue in utils.c to include <sys/time> but not time

Suggesting improvements in makefiles (.am), instead of forcing to have folder 'common' would be better to have relative include $(srcdir) in AM_CPPFLAGS.

1) AM_CPPFLAGS = -I$(srcdir)/rb_tree 
AM_CPPFLAGS = -I$(srcdir)/rb_tree 

instead of 

AM_CPPFLAGS = -I$(top_srcdir)/common/libinterval3/rb_tree

2) 

libinterval3_la_SOURCES = \
	interval_tree.c

libinterval3_la_LIBADD = rb_tree/librbtree.la \
			$(CONDITIONAL_LIBS)

instead of

libinterval3_la_LIBADD = $(top_builddir)/common/libinterval3/rb_tree/librbtree.la \
			$(CONDITIONAL_LIBS)

3) Remove header from 
libinterval3_la_SOURCES = \
	interval_tree.c interval_tree.h


because headers dont belong in *_SOURCES. They should only be included in AM_CPPFLAGS of needed.

4) Add short CmakeLists.txt

add_library(cccommon
    libpatricia/patricia.c
    //rest if needed kuje libinterval3/interval_tree.h (for interval tree the red black tree as well)
)

# Add include directories
target_include_directories(cccommon PUBLIC
    ${CMAKE_CURRENT_SOURCE_DIR}
    ${CMAKE_CURRENT_SOURCE_DIR}/libpatricia
    .... // the rest if needed like ${CMAKE_CURRENT_SOURCE_DIR}/libcsv
    etc.
)

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In improved case user can submodule the cc-common to any directory such as **lib/cccommon**. 

In the source proeject CMakeLists.txt to add subdirectory to invoke short CMakeLists.txt and link it.

add_subdirectory(lib/cccommon)
target_include_directories(my_project_name PRIVATE
    ${CMAKE_SOURCE_DIR}/lib/cccommon
    ${CMAKE_SOURCE_DIR}/lib/cccommon/libpatricia
    // and the rest like ${CMAKE_SOURCE_DIR}/lib/cccommon/libcsv
    //etc.
)

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packges: autoconf automake libtool
----------------------------
autoreconf -i
 ./configure
make
-------------
cmake -S . -B
cmake --build build