Copy install_geos.sh from master (from shapely#1042)

ci/install_geos.sh

@@ -0,0 +1,70 @@
+#!/bin/sh
+
+# Build and install GEOS on a POSIX system, save cache for later
+#
+# This script requires environment variables to be set
+#  - export GEOS_INSTALL=/path/to/cached/prefix -- to build or use as cache
+#  - export GEOS_VERSION=3.7.3 or master -- to download and compile
+
+set -e
+
+if [ -z "$GEOS_INSTALL" ]; then
+    echo "GEOS_INSTALL must be set"
+    exit 1
+elif [ -z "$GEOS_VERSION" ]; then
+    echo "GEOS_VERSION must be set"
+    exit 1
+fi
+
+# Create directories, if they don't exit
+mkdir -p $GEOS_INSTALL
+
+# Download and build GEOS outside other source tree
+GEOS_BUILD=$HOME/geosbuild
+
+prepare_geos_build_dir(){
+  rm -rf $GEOS_BUILD
+  mkdir -p $GEOS_BUILD
+  cd $GEOS_BUILD
+}
+
+build_geos(){
+    echo "Building geos-$GEOS_VERSION"
+    mkdir build
+    cd build
+    cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$GEOS_INSTALL ..
+    make -j 2
+    ctest .
+    make install
+}
+
+if [ "$GEOS_VERSION" = "master" ]; then
+    prepare_geos_build_dir
+    # use GitHub mirror
+    git clone --depth 1 https://github.com/libgeos/geos.git geos-$GEOS_VERSION
+    cd geos-$GEOS_VERSION
+    git rev-parse HEAD > newrev.txt
+    BUILD=no
+    # Only build if nothing cached or if the GEOS revision changed
+    if test ! -f $GEOS_INSTALL/rev.txt; then
+        BUILD=yes
+    elif ! diff newrev.txt $GEOS_INSTALL/rev.txt >/dev/null; then
+        BUILD=yes
+    fi
+    if test "$BUILD" = "no"; then
+        echo "Using cached install $GEOS_INSTALL"
+    else
+        cp newrev.txt $GEOS_INSTALL/rev.txt
+        build_geos
+    fi
+else
+    if [ -d "$GEOS_INSTALL/include/geos" ]; then
+        echo "Using cached install $GEOS_INSTALL"
+    else
+        prepare_geos_build_dir
+        wget -q http://download.osgeo.org/geos/geos-$GEOS_VERSION.tar.bz2
+        tar xfj geos-$GEOS_VERSION.tar.bz2
+        cd geos-$GEOS_VERSION
+        build_geos
+    fi
+fi