newapkbuild: fix empty function regression

Since the obsolete 'cd "$builddir"' statements have been removed in [1],
build(), check() and package() can generate empty functions if no build
system is specified or if there is no default for the given build
system. newapkbuild will then fail, as it tries to parse the script it
generated:

$ cd /home/pmos && newapkbuild test
/usr/bin/abuild: /home/pmos/test/APKBUILD: line 18: syntax error: unexpected "}"
$ cat test/APKBUILD
...
build() {
}
...

Fix this by placing ":" in functions that would be empty.

[1]: f83d19ce79ab9f2dcc5238346a910cd18ae0f330

0 files changed, 0 insertions, 0 deletions