Finish preprocessor. Now it correctly handles $IFDEF, $IFNDEF, $ELSE, $ENDIF and $DEFINE.
Still not enterprise level, as has some flaws, but is okay to process hedgewars sources.
INCLUDEPATH += $$PWD
DEPENDPATH += $$PWD
HEADERS += $$PWD/crypt.h \
$$PWD/ioapi.h \
$$PWD/JlCompress.h \
$$PWD/quaadler32.h \
$$PWD/quachecksum32.h \
$$PWD/quacrc32.h \
$$PWD/quazip.h \
$$PWD/quazipfile.h \
$$PWD/quazipfileinfo.h \
$$PWD/quazipnewinfo.h \
$$PWD/unzip.h \
$$PWD/zip.h
SOURCES += $$PWD/qioapi.cpp \
$$PWD/JlCompress.cpp \
$$PWD/quaadler32.cpp \
$$PWD/quacrc32.cpp \
$$PWD/quazip.cpp \
$$PWD/quazipfile.cpp \
$$PWD/quazipnewinfo.cpp \
$$PWD/unzip.c \
$$PWD/zip.c