The intended effect (building a Windows "GUI" application), is
correctly achieved using the "WIN32" option of add_executable()
selectively where appropriate rather than setting this platform
specific option for *all* (Windows) executables when using GNU
compilers (MinGW, MSYS2, Cygwin, ...).
According to PR #415 this switch was added in Visual Studio 2015
Update 3. However, version "1900" does not distinguish updates,
hence Visual Studio 2015 up to Update 2 may fail to compile with
this addition. Installing the updates would obviously fix this.
The source files are all encoded by UTF-8 without BOM. This will raise
warnings and errors when compiling by the MSVC with some active code
pages (ACP). The file `test/ask.cxx` contains such characters with UTF-8
encoding. Adding `/utf-8` here is equivalent to specifying
`/source-charset:utf-8 /execution-charset:utf-8`, and all warnings and
errors are removed.
Although CMake uses previously undefined variables like empty strings
it could happen that variables set in the calling context by other
projects initialized some variables with unexpected values.
Example: FLTK_LIBRARIES could have been initialized by previous
execution of 'find_package(FLTK ...)' in a project using FLTK
These two functions are fully defined in the platform specific driver
methods, there's no need to define them in the base class.
This quick fix returns 0 from the base class method. The main reason
was to avoid a compiler error of MSVC 2010 and earlier, i.e. before
MSVC 2012.
Todo: int Fl_WinAPI_System_Driver::clocale_sscanf() needs to be fixed
because '_vsscanf_l()' (with lower case 'L' for 'locale') does not
exist in MSVC 2010 and earlier. It is not clear yet in which version
it was added - current MS docs show it in MSVC 2015 and later.
Note that this fix includes "../src/flstring.h" which makes the source
file no longer compileable without the full source code, e.g. by
using "fltk-config --compile ...". This might be fixed later. (?)
Code like "void copy(const char */*stuff*/, ...)" would issue the
warning "'*/' seen outside comment" which is formally true but ...
These warnings don't appear with newer MS compilers, but I fixed them
anyway.
Remove false "optimization" that would return the same pointer
if the requested width and height are the same.
Note: copy() must always return a new image (this is the expected
behavior of copy). Otherwise deleting one of the objects (either
the source or the copy) would delete the other one as well.
