fix README.md links

fixed broken link to fork and gitlab page in readme file

See merge request !27

Set up GitLab CI

This merge request is now ready. Build with gcc and clang works, all tests pass except tests.aconversion.sh (see #83). The last complete build is [pipelines/917](https://gitlab.fit.cvut.cz/travnja3/automata-library/pipelines/917).

Jobs may sometimes fail due to not enough space on disk, I’m gonna fix this problem soon.

See merge request !25

fix includes of wait.h and sys/fcntl.h to use standard locations

POSIX standard specifies that wait.h should be in sys/wait.h and
fcntl.h at top-level, not under sys. This is true for all unix systems,
even glibc. glibc provides wait.h and sys/fcntl.h, but these just
includes the same-named headers from the correct locations.

See merge request !26

POSIX standard specifies that wait.h should be in sys/wait.h and
fcntl.h at top-level, not under sys. This is true for all unix systems,
even glibc. glibc provides wait.h and sys/fcntl.h, but these just
includes the same-named headers from the correct locations.

include <sys/types.h> where uint is used

Compilation fails on gcc 6.3.0 and musl libc:

    g++ -pipe -std=c++11 -O3 -DNDEBUG -DRELEASE -c -Wall -pedantic -Wextra -Werror \
      -Wshadow -Wpointer-arith -Wcast-qual -Wdelete-non-virtual-dtor \
      -Wredundant-decls -fPIC \
      ... \
      alib2algo_experimental/src/graph/spanningtree/Kruskal.cpp \
      -o alib2algo_experimental/obj-release/graph/spanningtree/Kruskal.o
    In file included from alib2algo_experimental/src/graph/spanningtree/Kruskal.cpp:15:0:
    alib2algo_experimental/src/graph/spanningtree/../datastructs/Components.h:74:3: error: 'uint' does not name a type
       uint parent;
       ^~~~

This type is defined in sys/types.h when _GNU_SOURCE or _BSD_SOURCE is
defined (at least in musl libc). Please note that uint is not specified
in C++ standard and should not be used...

See merge request !23

Compilation fails on gcc 6.3.0 and musl libc:

  g++ -pipe -std=c++11 -O3 -DNDEBUG -DRELEASE -c -Wall -pedantic -Wextra -Werror \
    -Wshadow -Wpointer-arith -Wcast-qual -Wdelete-non-virtual-dtor \
    -Wredundant-decls -fPIC \
    ... \
    alib2algo_experimental/src/graph/spanningtree/Kruskal.cpp \
    -o alib2algo_experimental/obj-release/graph/spanningtree/Kruskal.o
  In file included from alib2algo_experimental/src/graph/spanningtree/Kruskal.cpp:15:0:
  alib2algo_experimental/src/graph/spanningtree/../datastructs/Components.h:74:3: error: 'uint' does not name a type
     uint parent;
     ^~~~

This type is defined in sys/types.h when _GNU_SOURCE or _BSD_SOURCE is
defined (at least in musl libc). Please note that uint is not specified
in C++ standard and should not be used...

makefile: add tasks test-debug and test-release

I've intentionally omitted dependency of test-* on build-*, to not
require building all modules when one have executables in bin-*.
However, when debug or release is invoked and RUN_TESTS is 1, then
it invokes build and test in this order.

See merge request !22

fix LD_LIBRARY_PATH in makefiles to not use semicolon

The current makefiles generate invalid LD_LIBRARY_PATHs like:

    LD_LIBRARY_PATH="../alib2std/lib-release;../alib2common/lib-release;lib-release" test-bin-release/alib2test

Standard directory separator on Unix/Linux systems is a colon. I found
that semicolon may be used to separate two lists of directories - the
first one is searched before the list(s) supplied on the command line,
the second one is searched after. But that's apparently not the case
here.

It seems that glibc doesn't care about it, because it somehow works on
Jenkins that runs on Gentoo. However, more correct libc libraries, like
musl libc, do care about it and don't accept such LD_LIBRARY_PATH.

See merge request !21

I've intentionally omitted dependency of test-* on build-*, to not
require building all modules when one have executables in bin-*.
However, when debug or release is invoked and RUN_TESTS is 1, then
it invokes build and test in this order.

The current makefiles generate invalid LD_LIBRARY_PATHs like:

    LD_LIBRARY_PATH="../alib2std/lib-release;../alib2common/lib-release;lib-release" test-bin-release/alib2test

Standard directory separator on Unix/Linux systems is a colon. I found
that semicolon may be used to separate two lists of directories - the
first one is searched before the list(s) supplied on the command line,
the second one is searched after. But that's apparently not the case
here.

It seems that glibc doesn't care about it, because it somehow works on
Jenkins that runs on Gentoo. However, more correct libc libraries, like
musl libc, do care about it and don't accept such LD_LIBRARY_PATH.

fix requirements in readme, add libxml2-dev



See merge request !20