drone build: Don't use pre-compiled cmake binary (Rasbats#199).

ci/drone-build-raspbian.sh

@@ -17,23 +17,28 @@ sudo apt-get -q --allow-unauthenticated install -f
 
 git fetch --all --tags
 
-# Temporary fix until 3.19 is available as a pypi package
-# 3.19 is needed: https://gitlab.kitware.com/cmake/cmake/-/issues/20568
-url='https://dl.cloudsmith.io/public/alec-leamas/opencpn-plugins-stable/deb/debian'
-wget $url/pool/${OCPN_TARGET/-*/}/main/c/cm/cmake-data_3.19.3-0.1_all.deb
-wget $url/pool/${OCPN_TARGET/-*/}/main/c/cm/cmake_3.19.3-0.1_armhf.deb
-sudo apt install ./cmake_3.19.3-0.1_armhf.deb ./cmake-data_3.19.3-0.1_all.deb
+# Initiate python setup
+apt-get install -q python3-pip python3-cryptography openssh-client
 
+deb_vers=$(lsb_release -rs)
+if [ $deb_vers -lt 10 ] ; then
+    # Latest pip 21.0.0 requires python 3.6+, we have only 3.5:
+    python3 -m pip install --user -q --force-reinstall pip==20.3.4 setuptools wheel
+
+    # Install a modern cmake, Debian's is too old.
+    python3 -m pip  install --user -q cmake==3.20.5
+else
+    # Install latest pip and cmake versions
+    python3 -m pip install --user -q --force-reinstall pip setuptools wheel
+    python3 -m pip  install --user -q cmake
+fi
+
+# configure and build
 rm -rf build; mkdir build; cd build
 cmake -DCMAKE_BUILD_TYPE=Release ..
 make -j $(nproc) VERBOSE=1 tarball
 ldd  app/*/lib/opencpn/*.so
 
-# Initiate python setup, install cryptography and ssh-client for git-push.
-apt-get install -q python3-pip python3-cryptography openssh-client
-
-# Latest pip 21.0.0 requires python 3.6+, we have only 3.5:
-python3 -m pip install --user -q --force-reinstall pip==20.3.4 setuptools wheel
 
 # Install cloudsmith-cli for upload script. 
 python3 -m pip install --user -q cloudsmith-cli