Improve the treatment of single line comment.

Make including library easier

libconfig can now be built by including with eg. add_subdirectory
directly, without changing compiler flags

Some changes for CMakeLists.txt - one bug-fix included

Setting this define makes that

    #include <stdlib.h>

does nothing (because of the include-guard). But this file
is needed for free() and realloc() and others.

The cmake built-in variable BUILD_SHARED_LIBS
does exactly what LIB_TYPE was used for. Switching between
SHARED and STATIC library-builds.

Fixed an issue causing build to fail on OSX 10.12.

#96 : fix lib/CMakeLists.txt, add wincompat.c.

Added optional method chained interface

AM_CONFIG_HEADER is deprecated

configure cmake

Safely handle escape sequences

And accompanying tests

fixed from PVS-Studio

V575 The potential null pointer is passed into 'fread' function. Inspect the first argument. tests.c 126