build.sh: always install Subsurface

We had not done this on Linux as it was just as easy to run from the build
environment, but we need to install in order to be able to create an AppImage
on Travis.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

scripts/build.sh

@@ -475,6 +475,7 @@ for (( i=0 ; i < ${#BUILDS[@]} ; i++ )) ; do
 		-DLIBDIVECOMPUTER_LIBRARIES=$INSTALL_ROOT/lib/libdivecomputer.a \
 		-DCMAKE_PREFIX_PATH=$CMAKE_PREFIX_PATH \
 		-DBTSUPPORT=${BTSUPPORT} \
+		-DCMAKE_INSTALL_PREFIX=${INSTALL_ROOT} \
 		$PRINTING $EXTRA_OPTS
 
 	if [ $PLATFORM = Darwin ] ; then
@@ -483,8 +484,5 @@ for (( i=0 ; i < ${#BUILDS[@]} ; i++ )) ; do
 	fi
 
 	LIBRARY_PATH=$INSTALL_ROOT/lib make -j4
-
-	if [ $PLATFORM = Darwin ] ; then
-		LIBRARY_PATH=$INSTALL_ROOT/lib make install
-	fi
+	LIBRARY_PATH=$INSTALL_ROOT/lib make install
 done