depends: Override host compilers for FreeBSD and OpenBSD #32716

1. 
   hebasto commented at 2:02 pm on June 10, 2025: member

   When building depends on FreeBSD/OpenBSD aarch64, the host compilers default to default_host_{CC,CXX}, which resolves to gcc/g++. This is incorrect on these systems, where Clang is the default system compiler.

   To ensure proper compiler selection, this PR adopts the same approach used for darwin:https://github.com/bitcoin/bitcoin/blob/c1d4253d316ea627f46b26e395d7b48842258381/depends/builders/darwin.mk#L12-L14

   Fixes #32691.

2. depends: Override host compilers for FreeBSD and OpenBSD

   When building depends on FreeBSD/OpenBSD `aarch64`, the host compilers
   default to `default_host_{CC,CXX}`, which resolves to `gcc`/`g++`. This
   is incorrect on these systems, where Clang is the default system
   compiler.

   4f10a57671
3. hebasto added the label Build system on Jun 10, 2025
4. 
   DrahtBot commented at 2:02 pm on June 10, 2025: contributor

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   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/32716.

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5. 
   Sjors commented at 3:35 pm on June 10, 2025: member

   ACK 4f10a57671c19cacca630b2401e42a213aacff1b

   I tested that this fixes #32691 on an aarch64 OpenBSD VM, and doesn’t break anything on an x86 VM.

   I didn’t test FreeBSD.

   While testing this I noticed the depends build doesn’t bother creating qt. It’s not obvious to me why that is and doesn’t seem to be documented. The non-depends instructions for *BSD do include qt6.

6. 
   hebasto commented at 4:08 pm on June 10, 2025: member

   cc @vasild
7. 
   hebasto commented at 2:44 pm on June 11, 2025: member

   Here is a CI build on FreeBSD aarch64 with depends: https://github.com/hebasto/bitcoin-core-nightly/actions/runs/15568752551/job/43839203600.
8. 
   theuni commented at 3:06 pm on June 11, 2025: member

   Since gcc (and thus $(host_toolchain)gcc) is basically never the right option for these, I’m wondering if we should just do something like:

    0diff --git a/depends/hosts/freebsd.mk b/depends/hosts/freebsd.mk
    1index 009d215f82f..0a9d8bb423d 100644
    2--- a/depends/hosts/freebsd.mk
    3+++ b/depends/hosts/freebsd.mk
    4@@ -7,25 +7,24 @@ freebsd_release_CXXFLAGS=$(freebsd_release_CFLAGS)
    5 freebsd_debug_CFLAGS=-O1 -g
    6 freebsd_debug_CXXFLAGS=$(freebsd_debug_CFLAGS)
    7
    8+freebsd_CC=clang
    9+freebsd_CXX=clang++
   10+
   11+ifneq ($(host),$(build))
   12+freebsd_CC+=-target $(canonical_host)
   13+freebsd_CXX+=-target $(canonical_host)
   14+endif
   15+
   16 ifeq (86,$(findstring 86,$(build_arch)))
   17-i686_freebsd_CC=clang -m32
   18-i686_freebsd_CXX=clang++ -m32
   19 i686_freebsd_AR=ar
   20 i686_freebsd_RANLIB=ranlib
   21 i686_freebsd_NM=nm
   22 i686_freebsd_STRIP=strip
   23
   24-x86_64_freebsd_CC=clang -m64
   25-x86_64_freebsd_CXX=clang++ -m64
   26 x86_64_freebsd_AR=ar
   27 x86_64_freebsd_RANLIB=ranlib
   28 x86_64_freebsd_NM=nm
   29 x86_64_freebsd_STRIP=strip
   30-else
   31-i686_freebsd_CC=$(default_host_CC) -m32
   32-i686_freebsd_CXX=$(default_host_CXX) -m32
   33-x86_64_freebsd_CC=$(default_host_CC) -m64
   34-x86_64_freebsd_CXX=$(default_host_CXX) -m64
   35 endif
   36
   37 freebsd_cmake_system_name=FreeBSD
   

9. 
   hebasto commented at 3:18 pm on June 11, 2025: member

   Since gcc (and thus $(host_toolchain)gcc) is basically never the right option for these, I’m wondering if we should just do something like…

   I’d considered this option and another one. I chose the current approach for two reasons: (a) it results in a minimal diff, and (b) it avoids changing compiler flags on the x86_64 and i686 build platforms.

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hebasto DrahtBot Sjors theuni

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