Use AC_PATH_PROG correctly:
-rw-r--r-- 6500 CREDITS.TXT
-rw-r--r-- 3157 LICENSE.TXT
-rw-r--r-- 5008 Makefile
-rw-r--r-- 2712 Makefile.common
-rw-r--r-- 8512 Makefile.config.in
-rw-r--r-- 62302 Makefile.rules
-rw-r--r-- 92 ModuleInfo.txt
-rw-r--r-- 483 README.txt
drwxr-xr-x - Xcode
drwxr-xr-x - autoconf
drwxr-xr-x - bindings
-rwxr-xr-x 1986 build-for-llvm-top.sh
-rwxr-xr-x 1100376 configure
drwxr-xr-x - docs
drwxr-xr-x - examples
drwxr-xr-x - include
drwxr-xr-x - lib
-rw-r--r-- 1890 llvm.spec.in
drwxr-xr-x - projects
drwxr-xr-x - runtime
drwxr-xr-x - test
drwxr-xr-x - tools
drwxr-xr-x - utils
drwxr-xr-x - website
drwxr-xr-x - win32