More updates to OS X Jenkins build script.

devtools/packaging/scripts/osx/build.sh

@@ -3,7 +3,8 @@
 # Build script for Mac OS X distribution, for use in automated packaging.
 # Note that this must be run from outside the checked-out openmm/ directory.
 
-PATH=$HOME/miniconda/bin:$PATH
+# Add conda binaries to path.
+PATH=${HOME}/miniconda/bin:${PATH}
 
 INSTALL=`pwd`/install
 CMAKE_FLAGS="-DCMAKE_INSTALL_PREFIX=$INSTALL"
@@ -26,10 +27,14 @@ CMAKE_FLAGS+=" -DFFTW_INCLUDES=$PREFIX/include"
 CMAKE_FLAGS+=" -DFFTW_LIBRARY=$PREFIX/lib/libfftw3f.so"
 CMAKE_FLAGS+=" -DFFTW_THREADS_LIBRARY=$PREFIX/lib/libfftw3f_threads.so"
 
+# Build in subdirectory.
+if [ -e build ]; then
+    rm -rf build
+fi
 mkdir build
 cd build
 cmake ../openmm $CMAKE_FLAGS
-make -j4
+make -j16
 make install
 
 # Install Python wrappers.