Check PRs for coding style issues.

.travis.yml

@@ -58,6 +58,7 @@ script:
   fi
 - export PATH=$PATH:$ESP_HOME/xtensa-lx106-elf/bin:$ESP_HOME/utils/:$SMING_HOME/../.travis/tools
 - cd $SMING_HOME
+- if [ "$SDK_VERSION" == "2.0.0" ]; then ../.travis/tools/clang/format-pr.sh; fi
 - make test
 - cd $SMING_HOME/../
 - export SMING_HAS_CHANGED=`for i in $CHANGED_FILES; do  if [[ $i == Sming/* ]]; then

.travis/tools/clang/format-pr.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+
+# Script taken from here: https://github.com/citra-emu/citra
+# and is distributed under the same license as the original script
+
+# Default clang-format points to default 3.5 version one
+CLANG_FORMAT=clang-format
+$CLANG_FORMAT --version
+
+cd $SMING_HOME/..
+
+# Get list of modified files
+files_to_lint="$(git diff --name-only --diff-filter=ACMRTUXB $TRAVIS_COMMIT_RANGE | grep '^[^.]*[.]\(c\|cpp\|h\)$' | grep -e Sming/SmingCore -e samples || true)"
+
+for f in $files_to_lint; do
+
+    d=$(diff -u "$f" <($CLANG_FORMAT "$f") || true)
+    if ! [ -z "$d" ]; then
+        echo "!!! $f not compliant to coding style, here is the fix:"
+        echo "$d"
+        fail=1
+    fi
+done
+
+if [ "$fail" = 1 ]; then
+    exit 1
+fi