Provide <triplet>-<tool> wrappers and links to many llvm tools

Provide wrappers named <triplet>-gcc and <triplet>-g++ as well,
to ease cross compilation with e.g. autotools, to allow just
specifying --host=<triplet>.

Provide wrappers for objdump and ld that provide specific output
that autotools look for.

Provide <triplet>-strip as a symlink to /bin/true, since there is
no strip tool available yet (and llvm-objcopy doesn't support
COFF yet).

wrappers/clang-target-wrapper.sh

@@ -1,7 +1,17 @@
 #!/usr/bin/env bash
 DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-TARGET="$(basename $0 | sed 's/-clang.*//')"
-EXE=$(basename $0 | sed 's/.*-\(clang.*\)/\1/')
+TARGET="$(basename $0 | sed 's/-[^-]*$//')"
+EXE=$(basename $0 | sed 's/.*-\([^-]*\)/\1/')
+case $EXE in
+clang*)
+    ;;
+gcc)
+    EXE=clang
+    ;;
+g++)
+    EXE=clang++
+    ;;
+esac
 ARCH=$(echo $TARGET | sed 's/-.*//')
 SYSROOT="$(cd "$DIR"/../$TARGET && pwd)"
 case $ARCH in