.travis.yml: Moving to xcode9.2 image for testing, as the stdio.h issue seems xcode related (probably a bug with 9.4). Removing header removal.

.travis.yml

@@ -62,16 +62,19 @@ matrix:
       compiler: clang
     # osx with gcc6
     - os: osx
+      osx_image: xcode9.2
       compiler: gcc
       env:
         - MATRIX_EVAL="CC=gcc-6 CXX=g++-6"
     # osx with gcc7
     - os: osx
+      osx_image: xcode9.2
       compiler: gcc
       env:
         - MATRIX_EVAL="CC=gcc-7 CXX=g++-7"
     # osx with gcc8
     - os: osx
+      osx_image: xcode9.2
       compiler: gcc
       env:
         - MATRIX_EVAL="CC=gcc-8 CXX=g++-8"
@@ -104,11 +107,7 @@ before_script:
 
 script:
     - if [ "$TRAVIS_OS_NAME" == "linux" ]; then ./waf configure --prefix=/usr --alsa --classic --dbus; fi
-    - if [ "$TRAVIS_OS_NAME" == "osx" ]; then
-        ./waf configure;
-        # force removal of include-fixed stdio.h
-        if [[ "${CC}" == "gcc-"* ]]; then sudo rm /usr/local/Cellar/gcc@*/*/lib/gcc/*/gcc/x86_64*/*/include-fixed/stdio.h; fi;
-      fi
+    - if [ "$TRAVIS_OS_NAME" == "osx" ]; then ./waf configure; fi
     - ./waf -v build
     - sudo ./waf -v install