Ensure source file is final argument passed to CC and CPP tools (#42)

GCC and Clang both expect to receive the source files being compiled as
their final arguments - putting options after them may be an error
depending on the semantics of the option. When generating CC and CPP
tool commands, ensure `$SRCS_SRCS` (the source file) is the final
argument.

Author: chrisnovakovic

Diff for: build_defs/cc.build_defs

@@ -722,7 +722,7 @@ def _library_cmds(c, compiler_flags, pkg_config_libs, pkg_config_cflags, extra_f
     """Returns the commands needed for a cc_library rule."""
     dbg_flags = _build_flags(compiler_flags, pkg_config_libs, pkg_config_cflags, c=c, dbg=True)
     opt_flags = _build_flags(compiler_flags, pkg_config_libs, pkg_config_cflags, c=c)
-    cmd_template = '$TOOLS_CC -c -I . ${SRCS_SRCS} %s %s'
+    cmd_template = '$TOOLS_CC -c -I . %s %s ${SRCS_SRCS}'
     if archive:
         cmd_template += ' && "$TOOLS_ARCAT" ar -r && "$TOOLS_AR" s "$OUT"'
     cmds = {