bug(developer): package compiler should warn on case mismatch for files

[mcdurdin]

The .kps will also need the filenames updating. Should I do it for you?
I'm kind of surprised there wasn't a warning about that.

Originally posted by @LornaSIL in keymanapp/keyboards#4136 (comment)

[mcdurdin]

Turns out the compiler is already doing its thing. There was a warning on the build but it did not show up because 'treat warnings as errors' is switched off for the repository at present:

06:34:16       luo_lakeside.kpj - info KM05002: Building experimental/l/luo_lakeside/luo_lakeside.kpj
06:34:16       luo_lakeside.kmn - info KM05002: Building experimental/l/luo_lakeside/source/luo_lakeside.kmn
06:34:16       luo_lakeside.kmn - info KM05006: experimental/l/luo_lakeside/source/luo_lakeside.kmn built successfully.
06:34:16       luo_lakeside.kps - info KM05002: Building experimental/l/luo_lakeside/source/luo_lakeside.kps
06:34:16       luo_lakeside.kps - hint KM04015: Language tag 'luo-Zzzz' in keyboard luo_lakeside is not minimal, and should be 'luo'.
06:34:16       luo_lakeside.kps - warn KM0400F: The file 'luo_lakeside_S.PNG' does not follow the recommended filename conventions. The extension should be all lower case, and the filename should include only alphanumeric characters, -, _, + and .
06:34:16       luo_lakeside.kps - warn KM0400F: The file 'luo_lakeside_U.PNG' does not follow the recommended filename conventions. The extension should be all lower case, and the filename should include only alphanumeric characters, -, _, + and .
06:34:16       luo_lakeside.kps - warn KM0400F: The file 'luo_lakeside_A.PNG' does not follow the recommended filename conventions. The extension should be all lower case, and the filename should include only alphanumeric characters, -, _, + and .
06:34:16       luo_lakeside.kps - warn KM0400F: The file 'luo_lakeside_A_S.PNG' does not follow the recommended filename conventions. The extension should be all lower case, and the filename should include only alphanumeric characters, -, _, + and .
06:34:16       luo_lakeside.kps - hint KM05009: File on disk 'luo_lakeside_S.png' does not match case of 'luo_lakeside_S.PNG' in source file; this is an error on platforms with case-sensitive filesystems.
06:34:16       luo_lakeside.kps - hint KM05009: File on disk 'luo_lakeside_U.png' does not match case of 'luo_lakeside_U.PNG' in source file; this is an error on platforms with case-sensitive filesystems.
06:34:16       luo_lakeside.kps - hint KM05009: File on disk 'luo_lakeside_A.png' does not match case of 'luo_lakeside_A.PNG' in source file; this is an error on platforms with case-sensitive filesystems.
06:34:16       luo_lakeside.kps - hint KM05009: File on disk 'luo_lakeside_A_S.png' does not match case of 'luo_lakeside_A_S.PNG' in source file; this is an error on platforms with case-sensitive filesystems.
06:34:16       luo_lakeside.kps - info KM05006: experimental/l/luo_lakeside/source/luo_lakeside.kps built successfully.
06:34:16       luo_lakeside.kpj - info KM05002: Building experimental/l/luo_lakeside/luo_lakeside.kpj
06:34:16       luo_lakeside.kpj - info KM05006: experimental/l/luo_lakeside/luo_lakeside.kpj built successfully.
06:34:16       luo_lakeside.kpj - info KM0500B: Project experimental/l/luo_lakeside/luo_lakeside.kpj built successfully.

Follow-ups:

• Hint KM05009 should be a warning, given it ends up with bad results on case-sensitive filesystems
• Should extract the build logs in the keyboards repository to make it easier to see all hints and warnings for a project
• Turn on 'treat warnings as errors' in the keyboards repo