cmake: explicitly disable openssl support for host-cmake

host-cmake will optionally link with openssl for the embedded copy of
libarchive if available, leaking host dependencies and possibly causing
build issues in case of compatibility issues - E.G. the host-cmake version
we have in 2017.02.x doesn't build against openssl-1.1.0+:

https://github.com/libarchive/libarchive/issues/810

The openssl support in libarchive is unlikely to be needed, so explicitly
disable it.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/cmake/cmake.mk

@@ -46,6 +46,7 @@ define HOST_CMAKE_CONFIGURE_CMDS
 			-DCMAKE_C_FLAGS="$(HOST_CMAKE_CFLAGS)" \
 			-DCMAKE_CXX_FLAGS="$(HOST_CMAKE_CXXFLAGS)" \
 			-DCMAKE_EXE_LINKER_FLAGS="$(HOST_LDFLAGS)" \
+			-DCMAKE_USE_OPENSSL:BOOL=OFF \
 			-DBUILD_CursesDialog=OFF \
 	)
 endef