lang/ghc88 [2020Q1]: undefined reference to `libiconv_xxxxxxx`

[Matthias Petermann <mp%petermann-it.de@localhost>]

Hello everyone,

I was very happy today that pkgsrc 2020q1 contains an updated haskell 
and Pandoc. Unfortunately I am currently struggling with a build problem
from ghc88 (which pandoc needs at build time).

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ld: 
/usr/pkgsrc/lang/ghc88/work/ghc-8.8.1/libraries/base/dist-install/build/libHSbase-4.13.0.0_p.a(iconv.p_o): 
in function `hs_iconv_open':
iconv.c:(.text.hs_iconv_open+0x1): undefined reference to `libiconv_open'
ld: 
/usr/pkgsrc/lang/ghc88/work/ghc-8.8.1/libraries/base/dist-install/build/libHSbase-4.13.0.0_p.a(iconv.p_o): 
in function `hs_iconv':
iconv.c:(.text.hs_iconv+0x1): undefined reference to `libiconv'
ld: 
/usr/pkgsrc/lang/ghc88/work/ghc-8.8.1/libraries/base/dist-install/build/libHSbase-4.13.0.0_p.a(iconv.p_o): 
in function `hs_iconv_close':
iconv.c:(.text.hs_iconv_close+0x1): undefined reference to `libiconv_close'
`gcc' failed in phase `Linker'. (Exit code: 1)
gmake[1]: *** [utils/iserv/ghc.mk:104: 
utils/iserv/stage2_p/build/tmp/ghc-iserv-prof] Error 1
gmake[1]: *** Waiting for unfinished jobs....
<<ghc: 9067992864 bytes, 454 GCs, 54366808/149271248 avg/max bytes 
residency (12 samples), 402M in use, 0.000 INIT (0.000 elapsed), 9.180 
MUT (9.918 elapsed), 3.830 GC (3.896 elapsed) :ghc>>

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I started with a fresh NetBSD 9.0 / amd64 installation and created a 
number of packages (including samba). Samba in turn installs libiconv 
from pkgsrc. I have seen that iconv also seems to exist in the base 
system. Could that be the cause? If so, how can I prevent this?

Thank you in advance!

Best regards
Matthias