use newer cmake for travis linux builds, revise build script

scripts/travis

@@ -3,10 +3,10 @@ set -e
 
 ./autogen.sh
 
-if [ "x$ARCH" = "xnative" ]; then
+if "x$ARCH" = "xnative"; then
 	# test autotools
 	./configure
-	if [ `uname` = "Darwin" ]; then
+	if `uname` = "Darwin"; then
 		# OS X runs out of resources if we run 'make -j check'
 		make check
 	else
@@ -17,23 +17,29 @@ if [ "x$ARCH" = "xnative" ]; then
 	make dist
 	tar zxvf libressl-*.tar.gz
 	cd libressl-*
-
-	# test cmake and ninja
 	mkdir build
 	cd build
-	cmake ..
-	make
+
+	# test cmake and ninja
+	if `uname` = "Darwin"; then
+		cmake ..
+		make
+	else
+		sudo apt-add-repository -y ppa:kalakris/cmake
+		sudo apt-get update
+		sudo apt-get install -y $ARCH-x-gcc cmake ninja-build
+		cmake .. -GNinja
+		make
+	fi
 else
 	CPU=i686
-	if [ "x$ARCH" = "xmingw64" ]; then
+	if "x$ARCH" = "xmingw64"; then
 		CPU=x86_64
 	fi
 	export CC=$CPU-w64-mingw32-gcc
 
-	if [ -z $(which $CC) ]; then
+	if ! hash $CC 2>/dev/null; then
 		# Update Ubuntu 12.04 with current mingw toolchain
-		sudo apt-get update
-		sudo apt-get install -y python-software-properties
 		sudo apt-add-repository -y ppa:tobydox/mingw-x-precise
 		sudo apt-get update
 		sudo apt-get install -y $ARCH-x-gcc make