Add -pedantic to Makefile.standalone to match production.

Makefile.standalone

 # The following variables will likely need to be modified, depending on where
 # and how you built LLVM & Clang. They can be overridden in a command-line
 # invocation of make, like:
 #
 #   make LLVM_SRC_PATH=<path> LLVM_BIN_PATH=<path> \
 #        LIBCXX_INSTALL_PATH=<path> CLANG_PATH=<path> ...
 #
 
 # LLVM_SRC_PATH is the path to the root of the checked out source code. This
 # directory should contain the configure script, the include/ and lib/
@@ skipping 74 matching lines @@
 LLVM_LDFLAGS := `$(LLVM_BIN_PATH)/llvm-config --libs` \
                 `$(LLVM_BIN_PATH)/llvm-config --ldflags` \
                 `$(LLVM_BIN_PATH)/llvm-config --system-libs`
 
 # It's recommended that CXX matches the compiler you used to build LLVM itself.
 CCACHE := `command -v ccache`
 CXX := CCACHE_CPP2=yes $(CCACHE) $(CLANG_PATH)/clang++
 
 CXXFLAGS := $(LLVM_CXXFLAGS) -std=c++11 -Wall -Wextra -Werror -fno-rtti \
         -fno-exceptions $(OPTLEVEL) $(ASSERTIONS) $(CXX_DEFINES) -g \
-        $(HOST_FLAGS) -Wno-error=unused-parameter \
+        $(HOST_FLAGS) -pedantic -Wno-error=unused-parameter \
         -I$(LIBCXX_INSTALL_PATH)/include/c++/v1 $(CXX_EXTRA)
 LDFLAGS := $(HOST_FLAGS) -L$(LIBCXX_INSTALL_PATH)/lib -Wl,--gc-sections \
         $(LD_EXTRA)
 
 SRCS = \
         assembler.cpp \
         assembler_ia32.cpp \
         IceCfg.cpp \
         IceCfgNode.cpp \
         IceELFObjectWriter.cpp \
@@ skipping 102 matching lines @@
         git diff -U0 `git merge-base HEAD master` | \
         PATH=$(LLVM_BIN_PATH):$(PATH) \
         $(LLVM_SRC_PATH)/../clang/tools/clang-format/clang-format-diff.py \
         -p1 -style=LLVM -i
 
 clean:
         rm -rf llvm2ice *.o $(OBJDIR)
 
 clean-all: clean
         rm -rf build/