fix arch armv4t being passed to linker when building boost.locale for iOS and tvOS

Author: kambala-decapitator

boost.sh

@@ -59,6 +59,7 @@ MACOS_SILICON_ARCHS=("arm64")
 IOS_ARCHS=("armv7" "arm64")
 IOS_SIM_ARCHS=("i386" "x86_64")
 MAC_CATALYST_ARCHS=("x86_64")
+TVOS_ARCH="arm64"
 
 # Applied to all platforms
 CXX_FLAGS=""
@@ -793,6 +794,23 @@ EOF
 
 bootstrapBoost()
 {
+    PATCHED_FILE="$BOOST_SRC/tools/build/src/tools/darwin.jam"
+    BACKUP_EXTENSION=bak
+    mv -f "$PATCHED_FILE.$BACKUP_EXTENSION" "$PATCHED_FILE"
+    # fixes boost passing `-arch arm` to linker which fails due to attempt to use armv4t
+    PATCHED_FALLBACK_ARCH=
+    if [[ "$1" == "iOS" ]]; then
+        if grep -Fq armv <<<"${IOS_ARCHS[*]}"; then
+            PATCHED_FALLBACK_ARCH=armv7
+        else
+            PATCHED_FALLBACK_ARCH=arm64
+        fi
+    elif [[ "$1" == "tvOS" ]]; then
+        PATCHED_FALLBACK_ARCH=$TVOS_ARCH
+    fi
+    test "$PATCHED_FALLBACK_ARCH" && \
+        sed -i ".$BACKUP_EXTENSION" -e "s/options = -arch arm ;/options = -arch $PATCHED_FALLBACK_ARCH ;/" "$PATCHED_FILE"
+
     cd_or_abort "$BOOST_SRC"
     if [[ -z $BOOST_LIBS ]]; then
         ./bootstrap.sh --without-libraries="${ALL_BOOST_LIBS// /,}"