fix(main/swi-prolog): perform 2 hostbuilds for 32-bit targets

one to obtain a working string for the "ABI" file, and the second one to produce artifacts for everything else that is not the "ABI" file.

fixes termux#22737

packages/swi-prolog/build.sh

@@ -3,6 +3,7 @@ TERMUX_PKG_DESCRIPTION="Most popular and complete prolog implementation"
 TERMUX_PKG_LICENSE="BSD 2-Clause"
 TERMUX_PKG_MAINTAINER="@termux"
 TERMUX_PKG_VERSION="9.3.17"
+TERMUX_PKG_REVISION=1
 TERMUX_PKG_SRCURL=https://www.swi-prolog.org/download/devel/src/swipl-${TERMUX_PKG_VERSION}.tar.gz
 TERMUX_PKG_SHA256=0c091d56ea8c941e3af760af24134f60e1e06b1379af8dcd42492c82f5b3ac46
 TERMUX_PKG_DEPENDS="libandroid-execinfo, libarchive, libcrypt, libgmp, libyaml, ncurses, openssl, ossp-uuid, readline, zlib, pcre2"
@@ -33,6 +34,27 @@ termux_pkg_auto_update() {
 	termux_pkg_upgrade_version "$version"
 }
 
+_do_host_build() {
+	# Recreate host build directory because previous builds could have been
+	# of a different word size (e.g. 32bit or 64bit)
+	rm -rf "$TERMUX_PKG_HOSTBUILD_DIR"
+	mkdir -p "$TERMUX_PKG_HOSTBUILD_DIR"
+	cd "$TERMUX_PKG_HOSTBUILD_DIR"
+	cmake "$TERMUX_PKG_SRCDIR"          \
+		-G "Ninja"                      \
+		$CMAKE_EXTRA_DEFS               \
+		-DINSTALL_DOCUMENTATION=OFF     \
+		-DSWIPL_PACKAGES=ON             \
+		-DUSE_GMP=OFF                   \
+		-DBUILD_TESTING=ON              \
+		-DSWIPL_SHARED_LIB=OFF          \
+		-DSWIPL_PACKAGES_BDB=OFF        \
+		-DSWIPL_PACKAGES_ODBC=OFF       \
+		-DSWIPL_PACKAGES_QT=OFF         \
+		-DSWIPL_PACKAGES_X=OFF
+	ninja
+}
+
 # We do this to produce:
 # a native host build to produce
 # boot<nn>.prc, INDEX.pl, ssl cetificate tests,
@@ -43,40 +65,45 @@ termux_step_host_build() {
 	termux_setup_cmake
 	termux_setup_ninja
 
+	CMAKE_EXTRA_DEFS=""
+	# do an inital host build without the 32-bit flags to get a binary that can be run
+	# to obtain the correct value for storing in the SWIPL_ABI_FILE
+	# (using the 32-bit flags during the host build step and not the cross build step
+	# appears to be one of the causes of https://github.com/termux/termux-packages/issues/22737 )
+	# however there could be other potential workarounds, one of which is explained in the thread,
+	# so it's hard to tell which is objectively the best solution overall.
+	# With this method, IF the -d flag is used on build-package.sh, that causes the runtime value
+	# of the swipl binary's abi_version() function to change also, but does not change the value
+	# detected by this host build binary, so that is an edge case where this method, as currently written, fails.
+	# the "convert error to warning" method from the thread would not fail that edge case,
+	# but in that case the actual contents of the "ABI" file and its original behavior of triggering an error
+	# are not respected, while this method makes an attempt to populate the "ABI" file
+	# with what seems like the correct value most of the time, and respect swi-prolog's original behavior of
+	# producing an error and closing if anything at all goes wrong with the "ABI" file.
+	_do_host_build
+	SWIPL_ABI="$("$TERMUX_PKG_HOSTBUILD_DIR"/src/swipl --abi-version)"
+
+	# for 32-bit targets, do another host build to get
+	# the actual host build binaries for everything else (preserves the preexisting behavior
+	# of the swi-prolog package in every other way that is not the bugged "ABI" file)
 	if [ $TERMUX_ARCH_BITS = 32 ]; then
 		export LDFLAGS=-m32
 		export CFLAGS=-m32
 		export CXXFLAGS='-m32 -funwind-tables'
 		CMAKE_EXTRA_DEFS="-DCMAKE_LIBRARY_PATH=/usr/lib/i386-linux-gnu"
-	else
-		CMAKE_EXTRA_DEFS=""
+		_do_host_build
+		unset LDFLAGS
+		unset CFLAGS
+		unset CXXFLAGS
 	fi
-
-	cmake "$TERMUX_PKG_SRCDIR"          \
-		-G "Ninja"                      \
-		$CMAKE_EXTRA_DEFS               \
-		-DINSTALL_DOCUMENTATION=OFF     \
-		-DSWIPL_PACKAGES=ON             \
-		-DUSE_GMP=OFF                   \
-		-DBUILD_TESTING=ON              \
-		-DSWIPL_SHARED_LIB=OFF          \
-		-DSWIPL_PACKAGES_BDB=OFF        \
-		-DSWIPL_PACKAGES_ODBC=OFF       \
-		-DSWIPL_PACKAGES_QT=OFF         \
-		-DSWIPL_PACKAGES_X=OFF
-	ninja
-
-	unset LDFLAGS
-	unset CFLAGS
-	unset CXXFLAGS
 }
 
 termux_step_pre_configure() {
 	LDFLAGS+=" -landroid-execinfo $($CC -print-libgcc-file-name)"
 }
 
 termux_step_post_make_install() {
-	# Remove host build because future builds may be
-	# of a different word size (e.g. 32bit or 64bit)
+	echo "$SWIPL_ABI" > "$TERMUX_PREFIX"/lib/swipl/ABI
+	# Remove host build directory to force host build step to always run
 	rm -rf "$TERMUX_PKG_HOSTBUILD_DIR"
 }