travis: add osx build

.travis.yml

@@ -14,10 +14,12 @@ env:
     - CCACHE_TEMPDIR=/tmp/.ccache-temp
     - CCACHE_COMPRESS=1
     - BASE_OUTDIR=$TRAVIS_BUILD_DIR/out
+    - SDK_URL=https://bitcoincore.org/depends-sources/sdks
 cache:
   apt: true
   directories:
   - depends/built
+  - depends/sdk-sources
   - $HOME/.ccache
 matrix:
   fast_finish: true
@@ -30,6 +32,8 @@ matrix:
       env: HOST=x86_64-unknown-linux-gnu RUN_TESTS=true GOAL="install" BITCOIN_CONFIG="--enable-glibc-back-compat"
     - compiler: "true 4"
       env: HOST=i686-pc-linux-gnu PACKAGES="g++-multilib" RUN_TESTS=true GOAL="install" BITCOIN_CONFIG="--enable-glibc-back-compat"
+    - compiler: "true 5"
+      env: HOST=x86_64-apple-darwin11 PACKAGES="gcc-multilib g++-multilib cmake libcap-dev libz-dev libbz2-dev" OSX_SDK=10.7 GOAL="deploy"
     - compiler: "true 6"
       env: HOST=x86_64-w64-mingw32 PACKAGES="nsis gcc-mingw-w64-x86-64 g++-mingw-w64-x86-64 binutils-mingw-w64-x86-64 mingw-w64-dev" GOAL="deploy"
     - compiler: "true 7"
@@ -39,7 +43,9 @@ install:
     - if [ -n "$PACKAGES" ]; then travis_retry sudo apt-get install --no-upgrade -qq $PACKAGES; fi
 before_script:
     - unset CC; unset CXX
-    - mkdir -p depends/SDKs
+    - mkdir -p depends/SDKs depends/sdk-sources
+    - if [ -n "$OSX_SDK" -a ! -f depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz ]; then wget $SDK_URL/MacOSX${OSX_SDK}.sdk.tar.gz -O depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz; fi
+    - if [ -n "$OSX_SDK" -a -f depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz ]; then tar -C depends/SDKs -xf depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz; fi
     - make $MAKEJOBS -C depends HOST=$HOST $DEP_OPTS || (echo "Build failure. Verbose build follows." && make -C depends V=1 HOST=$HOST $DEP_OPTS)
 script:
     - OUTDIR=$BASE_OUTDIR/$TRAVIS_PULL_REQUEST/$TRAVIS_JOB_NUMBER-$HOST