From 09fb20182a727b9b0959cafb2ed2b6cb845adac3 Mon Sep 17 00:00:00 2001
From: Tom Reynolds <tomreyn@users.noreply.github.com>
Date: Sun, 8 Dec 2013 23:00:25 +0100
Subject: [PATCH] - Enable clang builds for Travis CI - build-mg.sh: Switch to
 clang build if CC and CXX env vars both contain 'clang'

---
 .travis.yml |  3 ++-
 build-mg.sh | 17 ++++++++++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index e22ba6c1..ee00496e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,10 @@
 language: cpp
 compiler:
   - gcc
-#  - clang
+  - clang
 before_install:
  - sudo apt-get update -qq # UPDATE REPOS
+ - sudo apt-cache policy
  - sudo mk/linux/setupBuildDeps.sh --quiet # INSTALL DEPENDENCIES HERE
 script:
 # ALL THE BUILD COMMANDS HERE
diff --git a/build-mg.sh b/build-mg.sh
index f8147921..24392ad4 100755
--- a/build-mg.sh
+++ b/build-mg.sh
@@ -7,6 +7,7 @@
 # to enable clang compilation: 
 # 1. sudo apt-get install clang
 # 2. Set the two vars below, WANT_CLANG=YES and CLANG_BIN_PATH=<path to the clang binary>
+#    OR: set both the CC and CXX environment variables to point to clang and clang++ respectively
 WANT_CLANG=NO
 CLANG_BIN_PATH=/usr/bin/
 
@@ -117,10 +118,24 @@ esac
 
 CURRENTDIR="$(dirname $(readlink -f $0))"
 
-if [ "$WANT_CLANG" = 'YES' ]; then 
+if [ "$WANT_CLANG" = 'YES' -o "`echo $CXX | grep -Fq 'clang'`" = 'clang' ]; then 
         EXTRA_CMAKE_OPTIONS="${EXTRA_CMAKE_OPTIONS} -DCMAKE_C_COMPILER=${CLANG_BIN_PATH}clang -DCMAKE_CXX_COMPILER=${CLANG_BIN_PATH}clang++"
         echo "USER WANTS to use CLANG / LLVM compiler! EXTRA_CMAKE_OPTIONS = ${EXTRA_CMAKE_OPTIONS}"
 #exit 1;
+elif [ "`echo $CC | grep -Fq 'clang'`" = 'clang' -a "`echo $CXX | grep -Fq 'clang'`" = 'clang' ]; then
+	if [ `echo $CC | grep -Fq '/'` = '/' ]; then
+		CLANG_CC=$CC
+	else
+		CLANG_CC=`which $CC`
+	fi
+	if [ `echo $CXX | grep -Fq '/'` = '/' ]; then
+		CLANG_CXX=$CXX
+	else
+		CLANG_CXX=`which $CXX`
+	fi
+        EXTRA_CMAKE_OPTIONS="${EXTRA_CMAKE_OPTIONS} -DCMAKE_C_COMPILER=${CLANG_CC} -DCMAKE_CXX_COMPILER=${CLANG_CXX}"
+        echo "USER WANTS to use CLANG / LLVM compiler! EXTRA_CMAKE_OPTIONS = ${EXTRA_CMAKE_OPTIONS}"
+#exit 1;
 fi
 
 echo "Calling cmake with EXTRA_CMAKE_OPTIONS = ${EXTRA_CMAKE_OPTIONS}"