From 15d512cc35106392ed7583d0e000d9a1b865f1e1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=A0imon=20Bo=C5=99ek?= <simon.borek@nic.cz>
Date: Mon, 27 Jun 2022 13:53:37 +0200
Subject: [PATCH 2/2] configure.ac: switch PLATFORM_TRIPLET suffix to '-musl'
 based on `host_os` instead of `build_os`

As `build_os` and `host_os` are results of autoconf's `AC_CANONICAL_BUILD`
and `AC_CANONICAL_HOST` macros[^1], the former refers to the system running the build
and the latter to the system that will run the compiled program.

`PLATFORM_TRIPLET` should refer to the target platform when cross-compiling.
Its libc related part should be therefore derived from the target platform as well
- which is currently not the case - `PLATFORM_TRIPLET` '-gnu' suffix is/isn't switched to '-musl'
based on `build-os` rather than `host-os` which leads to error message[^2]
and build failure when compiling Python on glibc system for musl target.

[^1]: https://www.gnu.org/software/autoconf/manual/autoconf-2.68/html_node/Canonicalizing.html ,
https://www.gnu.org/software/autoconf/manual/autoconf-2.68/html_node/Specifying-Target-Triplets.html
[^2]: "internal configure error for the platform triplet, please file a bug report"

Co-authored-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Šimon Bořek <simon.borek@nic.cz>
---
 configure    | 2 +-
 configure.ac | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/configure
+++ b/configure
@@ -5376,7 +5376,7 @@ EOF
 
 if $CPP $CPPFLAGS conftest.c >conftest.out 2>/dev/null; then
   PLATFORM_TRIPLET=`grep -v '^#' conftest.out | grep -v '^ *$' | tr -d ' 	'`
-  case "$build_os" in
+  case "$host_os" in
   linux-musl*)
     PLATFORM_TRIPLET=`echo "$PLATFORM_TRIPLET" | sed 's/linux-gnu/linux-musl/'`
     ;;
--- a/configure.ac
+++ b/configure.ac
@@ -866,7 +866,7 @@ EOF
 
 if $CPP $CPPFLAGS conftest.c >conftest.out 2>/dev/null; then
   PLATFORM_TRIPLET=`grep -v '^#' conftest.out | grep -v '^ *$' | tr -d ' 	'`
-  case "$build_os" in
+  case "$host_os" in
   linux-musl*)
     PLATFORM_TRIPLET=`echo "$PLATFORM_TRIPLET" | sed 's/linux-gnu/linux-musl/'`
     ;;
