I'm trying to build single package for plasma (kde5), with AlienBob kde.SlackBuild, and for some package I've no result, no package built, no errors. My system is a pure x86_64 multilib system with kde4 replaced with plasma, and every package has been installed.
Here are 2 examples of rebuilding with log results: akonadi and baloo.

I executed the following command for baloo:

./kde.SlackBuild frameworks:baloo 2>&1 | tee build-baloo-log.txt

and for akonadi:

./kde.SlackBuild applications:akonadi 2>&1 | tee build-baloo-log.txt

nota: I modified the SlackBuild with 'set -x' option to see every line of the executing script, and I don't understand the results of the logs.

Attached Files

	build-baloo-log.txt (55.7 KB, 32 views)
	build-akonadi-log.txt (95.2 KB, 27 views)

I had a cursory look at the baloo log -- without even looking at the build script itself. It looks like a table of names is scanned -- e.g. at line 1477 and following I see:
So I searched for "baloo = baloo" and found at line 1307:
So what results does building with baloo5 give?

Indeed some packages are named a bit differently than their source tarball suggests. This was meant to prevent clashes with packages that are in Slackware-current itself.
In the "pkgsrc" directory you will find all the package names for which the source tarball has a different name. The actual source is inside the file:
And therefore compiling the baloo source results in a baloo5 package, as follows:

ok for baloo5, but for akonadi:

./kde.SlackBuild applications:akonadi

gives nothing. What's wrong with this one.

I.e:

I think I understood the subtility.
Thanks Mr Bob.

libktorrent fails to be rebuilt:
--------------
[ 4%] Building CXX object src/CMakeFiles/KF5Torrent.dir/util/fileops.cpp.o
/tmp/kde_build/applications-extra/libktorrent-2.1.1/src/util/fileops.cpp: In function ‘bool bt::XfsPreallocate(const QString&, bt::Uint64)’:
/tmp/kde_build/applications-extra/libktorrent-2.1.1/src/util/fileops.cpp:369:36: error: invalid user-defined conversion from ‘QByteArray’ to ‘const char*’ [-fpermissive]
369 | int fd = ::open(QFile::encodeName(path), O_RDWR | O_LARGEFILE);
| ~~~~~~~~~~~~~~~~~^~~~~~
In file included from /usr/include/qt5/QtCore/QByteArray:1,
from /tmp/kde_build/applications-extra/libktorrent-2.1.1/src/util/fileops.h:25,
from /tmp/kde_build/applications-extra/libktorrent-2.1.1/src/util/fileops.cpp:21:
/usr/include/qt5/QtCore/qbytearray.h:450:5: note: candidate is: ‘QByteArray::operator QNoImplicitBoolCast() const’ <near match>
450 | operator QNoImplicitBoolCast() const;
| ^~~~~~~~
/usr/include/qt5/QtCore/qbytearray.h:450:5: note: no known conversion from ‘QNoImplicitBoolCast’ {aka ‘int’} to ‘const char*’
/tmp/kde_build/applications-extra/libktorrent-2.1.1/src/util/fileops.cpp:369:64: error: ‘QByteArray::operator QNoImplicitBoolCast() const’ is private within this context
369 | int fd = ::open(QFile::encodeName(path), O_RDWR | O_LARGEFILE);
| ^
In file included from /usr/include/qt5/QtCore/QByteArray:1,
from /tmp/kde_build/applications-extra/libktorrent-2.1.1/src/util/fileops.h:25,
from /tmp/kde_build/applications-extra/libktorrent-2.1.1/src/util/fileops.cpp:21:
/usr/include/qt5/QtCore/qbytearray.h:450:5: note: declared private here
450 | operator QNoImplicitBoolCast() const;
| ^~~~~~~~
In file included from /tmp/kde_build/applications-extra/libktorrent-2.1.1/src/util/fileops.cpp:30:
/usr/include/fcntl.h:195:30: note: initializing argument 1 of ‘int open(const char*, int, ...)’
195 | extern int open (const char *__file, int __oflag, ...) __nonnull ((1));
| ~~~~~~~~~~~~^~~~~~
make[2]: *** [src/CMakeFiles/KF5Torrent.dir/build.make:206: src/CMakeFiles/KF5Torrent.dir/util/fileops.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:619: src/CMakeFiles/KF5Torrent.dir/all] Error 2
make: *** [Makefile:141: all] Error 2
applications-extra:libktorrent failed to build.
------------------

Reported and fixed in https://bugs.kde.org/show_bug.cgi?id=414050

kio-extras fails to be rebuilt:
------------------------
/usr/bin/ld: CMakeFiles/kio_sftp.dir/kio_sftp.cpp.o: in function `sftpProtocol::sftpGet(QUrl const&, int&, long long, int)':
kio_sftp.cpp:(.text+0xc073): undefined reference to `sftp_lstat'
/usr/bin/ld: kio_sftp.cpp:(.text+0xc0aa): undefined reference to `sftp_attributes_free'
/usr/bin/ld: kio_sftp.cpp:(.text+0xc1d8): undefined reference to `sftp_attributes_free'
/usr/bin/ld: kio_sftp.cpp:(.text+0xc1fa): undefined reference to `sftp_open'
/usr/bin/ld: kio_sftp.cpp:(.text+0xc21a): undefined reference to `sftp_read'
/usr/bin/ld: kio_sftp.cpp:(.text+0xc2cf): undefined reference to `sftp_rewind'
/usr/bin/ld: kio_sftp.cpp:(.text+0xc49d): undefined reference to `sftp_get_error'
/usr/bin/ld: kio_sftp.cpp:(.text+0xc511): undefined reference to `sftp_seek64'
collect2: error: ld returned 1 exit status
make[2]: *** [sftp/CMakeFiles/kio_sftp.dir/build.make:129: bin/sftp.so] Error 1
make[1]: *** [CMakeFiles/Makefile2:7735: sftp/CMakeFiles/kio_sftp.dir/all] Error 2
make: *** [Makefile:130: all] Error 2
applications:kio-extras failed to build.
-----------------------