SUMMARY
KDevelop fails to build currently with 2 errors:

cmListFileLexer.c: In function 'cmListFileLexer_yy_init_buffer':
cmListFileLexer.c:1802:48: error: implicit declaration of function 'fileno'; did you mean 'mblen'? [-Werror=implicit-function-declaration]
cmListFileLexer.in.l: In function 'cmListFileLexerSetToken':
cmListFileLexer.in.l:290:25: error: implicit declaration of function 'strdup'; did you mean 'strcmp'? [-Werror=implicit-function-declaration]

STEPS TO REPRODUCE
1. Get a Musl based system like Gentoo Musl or Alpine Linux
2. Try to compile KDevelop

OBSERVED RESULT

A build failure happens "implicit declaration of function 'fileno'" and "implicit declaration of function 'strdup'".

EXPECTED RESULT

The application to compile correctly.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Alpine Linux
(available in About System)
KDE Plasma Version: 5.16.5
KDE Frameworks Version: 5.61.0
Qt Version: 5.12.4

ADDITIONAL INFORMATION

This system is Musl based, which is most probably the reason it doesn't work.