Use posix shell variable expansion substitution instead of subshells with sed

wrappers/clang-target-wrapper.sh

@@ -1,8 +1,9 @@
 #!/bin/sh
 DIR="$(cd "$(dirname "$0")" && pwd)"
-TARGET="$(basename $0 | sed 's/-[^-]*$//')"
-EXE=$(basename $0 | sed 's/.*-\([^-]*\)/\1/')
-ARCH=$(echo $TARGET | sed 's/-.*//')
+BASENAME="$(basename "$0")"
+TARGET="${BASENAME%-*}"
+EXE="${BASENAME##*-}"
+ARCH="${TARGET%%-*}"
 
 # Allow setting e.g. CCACHE=1 to wrap all building in ccache.
 if [ -n "$CCACHE" ]; then