Bug 1403346 - Use AC_SUBST_LIST for LLVM_CXXFLAGS. r=glandium

MozReview-Commit-ID: bsX83492AP

build/autoconf/clang-plugin.m4

@@ -157,7 +157,7 @@ if test -n "$ENABLE_CLANG_PLUGIN"; then
 fi
 
 AC_SUBST_LIST(CLANG_PLUGIN_FLAGS)
-AC_SUBST(LLVM_CXXFLAGS)
+AC_SUBST_LIST(LLVM_CXXFLAGS)
 AC_SUBST(LLVM_LDFLAGS)
 AC_SUBST(CLANG_LDFLAGS)