android: try harder to force PIE for android 5+

This may work around ghc's -no-pie flag. Untested.

standalone/android/toolchainpath

@@ -0,0 +1,56 @@
+#!/bin/sh
+# Outputs a new PATH setting that is prefixed by the path to the
+# Android cross-compiler toolchain to use for a given Android version.
+#
+# For Android 5, force PIE build flags
+#
+# Since the ghc-android wrappers actually hardcode the path to the
+# toolchain, and we want to wrap the toolchain programs, the binaries
+# are moved to bin/orig/ and replaced by wrappers.
+
+androidversion="$1"
+
+wrap () {
+	sed -e "s!PROG!$1!" -e "s!OPTS!$3!" < wrapper.pl > "$2"
+	chmod +x "$2"
+}
+
+# Allow running from the top or inside this directory.
+if [ -e abiversion ]; then 
+	abiversion=$(cat abiversion)
+else
+	abiversion=$(cat standalone/android/abiversion)
+fi
+
+# location to toolchain as installed by ghc-android
+androidtoolchain="$HOME/.ghc/$abiversion/bin"
+
+mkdir -p "$androidtoolchain/orig"
+
+for f in $(find "$androidtoolchain" -maxdepth 1 -not -type d -printf '%f\n'); do
+	bin="$androidtoolchain/$f"
+	orig="$androidtoolchain/orig/$f"
+	if [ ! -e "$orig" ]; then
+		cp -a "$bin" "$orig"
+	fi
+	if [ "$androidversion" = 5 ]; then
+		case "$f" in
+		*-ld*)
+			wrap "$orig" "$bin" "-pie"
+		;;
+		*-gcc)
+			wrap "$orig" "$bin" "-pie -fPIE"
+		;;
+		*'-g++')
+			wrap "$orig" "$bin" "-pie -fPIE"
+		;;
+		*)
+			cp -a "$orig" "$bin"
+		;;
+		esac
+	else
+		cp -a "$orig" "$bin"
+	fi
+done
+
+echo "$androidtoolchain:$PATH"