Add initial version of CMakeLists.txt files

[vbaderks]

This commit introduced 2 CMakeLists.txt files. The main CMakeLists.txt defines the global options of the project and defined the jpeg library. The second CMakeLists.txt defines the command line tool that uses the library.
The main 3 C++ compilers: MSVC, CGG and clang are supported).

Note: the shared library on Linux builds requires a source code update to ensure not all functions are exported by default.

[Jamaika1]

Problem with GCC 10.2.0.
Is this lossless JPEG project abandoned?
JPEG XT works in c++11 with -ggdb3 -flto -fPIC. Oddly enough, it won't be compatible with other libraries.

[mjpeg @ 000002436b9f2f00] Found EOI before any SOF, ignoring=0/0
[mjpeg @ 000002436b9f2f00] No JPEG data found in image
[image2 @ 000002436b9e0c00] decoding for stream 0 failed
[image2 @ 000002436b9e0c00] Could not find codec parameters for stream 0 (Video: mjpeg, none(bt470bg/unknown/unknown)): unspecified size
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, image2, from 'image_21448_24bit.jpg':
  Duration: 00:00:00.04, start: 0.000000, bitrate: 58633 kb/s
    Stream #0:0: Video: mjpeg, none(bt470bg/unknown/unknown), 25 fps, 25 tbr, 25 tbn, 25 tbc
[mjpeg @ 000002436b9f3700] mjpeg: unsupported coding type (c9)
[mjpeg @ 000002436b9f3700] Can not process SOS before SOF, skipping
[mjpeg @ 000002436b9f3700] Found EOI before any SOF, ignoring
[mjpeg @ 000002436b9f3700] No JPEG data found in image
    nan M-V:    nan fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0

[thorfdbg]

Am 20.02.21 um 09:14 schrieb Jamaika1:

Problem with GCC 10.2.0. Is this lossless JPEG project abandoned?

No. But is the program whose output you are showing here actually using this very library? I doubt it.

[chafey]

Any chance we can get this PR merged?