wrappers: make wrappers compatible with autotools. again.

wrappers/clang-ccache.in

 #!/usr/bin/env bash
 
-printf -v ARGS "%q " "$@"
-
-${CCACHE} ${LLVM_C_COMPILER} $ARGS
+exec ${CCACHE} ${LLVM_C_COMPILER} "$@"

wrappers/clang-hash-stop.in

@@ -3,8 +3,10 @@
 # Wrapper for clang, that supports (only) fast hash-based
 # recompilation.
 
-printf -v ARGS "%q " "$@"
-
-${LLVM_C_COMPILER} -fplugin=${PROJECT_BINARY_DIR}/src/libclang-hash.so \
-                   -Xclang -plugin-arg-clang-hash -Xclang -stop-if-same-hash \
-                   $ARGS
+if [[ ( "$@" =~ ".* -c .*") && ( "$@" =~ ".* -o. *" ) && ! ( "$@" =~ ".*/dev/null" ) ]]; then
+    exec ${LLVM_C_COMPILER} -fplugin=${PROJECT_BINARY_DIR}/src/libclang-hash.so \
+         -Xclang -plugin-arg-clang-hash -Xclang -stop-if-same-hash \
+         "$@"
+else
+    exec ${LLVM_C_COMPILER} "$@"
+fi